Hardening composition and hardened product

ABSTRACT

The present invention is directed to a hardening composition characterized by comprising (A) a slag composition containing 0 to 37 wt. % of CaO, 23 to 90 wt. % of SiO 2 , and 0 to 40 wt. % of Al 2  O 3  and 0.1 to 50 wt. % of one or more compounds selected from the group consisting of iron oxide, alkali components, phosphorous components, titanium dioxide, manganese oxide, and magnesium oxide, and/or 0.1 to 10 wt. % of a halogen; and (B) an alkaline activator. The invention is also directed to a hardened product obtained by mixing the hardening composition with water. The properties of the hardened product are suitable for use as various concrete materials, and therefore, refuse-incinerated ashes sewage sludge, etc. are effectively utilized and recycled as a resource.

TECHNICAL FIELD

The present invention relates to a hardening composition which containsa slag composition and to a hardened product thereof, and morespecifically to a hardening composition prepared through use of acomposition produced by converting various wastes into the form of afused slag. The hardening composition is capable of forming a hardenedproduct having excellent strength when mixed with water and cured, andis used as material for mortar, concrete, and the like.

BACKGROUND ART

Conventionally, cement has been widely used as a hardening compositionfor use in mortar, concrete, and the like. Cement as represented byportland cement is obtained by burning in a kiln a material compositionwhich contains limestone as a principal material, and which is aso-called hydraulic material which hardens through hydration.

Granulated blast furnace slag is known as a hardening material to bemixed with portland cement. Granulated blast furnace slag is obtained ina pig iron manufacturing process, is composed mainly of the threecomponents SiO₂, Al₂ O₃, and CaO, and normally has the followingcomposition: CaO 38-45%, SiO₂ 33-35%, Al₂ O₃ 14-18%, MgO 4-8%, and Fe₂O₃ 0.5-2%. Granulated blast furnace slag is produced by quenching moltenslag that comes from a blast furnace. Because of quenching, granulatedblast furnace is mostly vitrified without being crystallized; thus,granulated blast furnace slag is said to have latent hydraulicity.Through stabilization granulated blast furnace slag hardens in the formof CaO-SiO₂ --H₂ O--based gel, and CaO content is said to be animportant factor for this hardening. Particularly, blast furnace cementcomposed of granulated blast furnace slag and portland cement isadvantageously used for harbor works, sewerage works, and wastewatertreatment works because of its high long-term strength and high chemicalresistivity, but has a drawback that care must be taken in curing due topoor surface hardening. Accordingly, there has been strong demand for agood hardening composition which can replace granulated blast furnaceslag.

Meanwhile, large cities in particular have various waste-relatedproblems such as treatment of sludge and municipal refuse and securingof a final disposal yard for various industrial wastes, includingconstruction waste. Thus, various investigations and research effortsregarding recycling of such wastes are actively under way.

Individual municipalities and apparatus manufacturers are developingtechnology for utilizing ashes which remain after sludge and municipalrefuse are incinerated in order to reduce their volume, as well astechnology for utilizing fused slag which is obtained when such ashesare melted in order to further reduce their volume. The thus-obtainedslag has begun to be used as material for roadbeds, aggregate of blocks,tiles, bricks, etc., but usage is on a very small scale due to technicaland price-related restrictions and a distribution problem. Such slag isnot at a stage of intensive utilization, but still constitutes aheadache for municipalities in that they must somehow dispose of it.

Regarding sludge, since 1975 the Ministry of Construction has beenconducting investigations and research efforts for recycling of sludge.Also, the Ministry of Construction subsidizes facilities for utilizingsludge in order to promote utilization of sludge. Further, since 1988the Ministry of Construction has been carrying out a model project forutilization of sludge resource wherein sludge products (roadbedmaterial, soil conditioner, etc.) are positively used in sewerageconstruction works.

Despite such long-term studies on utilization of sludge and refuse,utilization of sludge-incinerated ashes and refuse-incinerated ashes aswell as their fused slag have not yet been remarkably implemented.

DISCLOSURE OF THE INVENTION

In order to find new hydraulic material which can replace granulatedblast furnace slag, the inventor has conducted various studies oncomposition and hardening performance of fused slags produced fromincineration ashes of various wastes. Unexpectedly, despite having a CaOcontent of not more than 37 wt. %, most fused slags produced fromsludge- and refuse-incinerated substances showed good hydraulicity whenalkali activators were added thereto, providing a hardened producthaving excellent strength. As a result of further study, it was foundthat a slag composition having a certain composition showed goodhydraulicity through addition of alkali activators, providing a hardenedproduct having excellent strength and thus leading to the achievement ofthe present invention.

Accordingly, the present invention provides a hardening compositioncharacterized by comprising:

(A) a slag composition containing 0 to 37 wt. % of CaO, 23 to 90 wt. %of SiO₂, and 0 to 40 wt. % of Al₂ O₃ and 0.1 to 50 wt. % of one or morecompounds selected from the group consisting of iron oxide, alkalicomponents, a phosphorous component, titanium dioxide, manganese oxide,and magnesium oxide, and/or 0.1 to 10 wt. % of a halogen; and

(B) an alkaline activators.

The present invention also provides a hardening compositioncharacterized by containing:

(A') a slag composition selected from the group consisting of fused slagproduced from a sludge-incinerated substance, fused slag produced from arefuse-incinerated substance, and fused slag produced from an industrialwaste-incinerated substance; and

(B) an alkaline activators.

BEST MODE FOR CARRYING OUT THE INVENTION

The slag composition (A) used in the present invention is a slagcomposition obtained by melting at high temperature a mixture of variousmaterials such as clay, limestone, a sludge-incinerated substance, arefuse-incinerated substance, and industrial waste, which are mixed soas to attain the above-described chemical composition, and thenquenching the melt. This mixture may be of commercially availablematerials. However, since most sludge-incinerated substances,refuse-incinerated substances, and industrial wastes have a chemicalcomposition falling within the above-described range, it is preferablethat they are used directly, in view of economy and utilization ofavailable resources.

The CaO content of the slag composition (A) is 0 to 37 wt. %, preferably1 to 37 wt. %, particularly preferably 1 to 35 wt. %. The SiO₂ contentis 23 to 90 wt. %, preferably 23 to 90 wt. %, particularly preferably 25to 90 wt. %. The Al₂ O₃ content is 0 to 40 wt. %, preferably 1 to 40 wt.%, particularly preferably 10 to 30 wt. %.

Also, in the slag composition (A), the weight ratio of CaO/SiO₂ isimportant for the development of strength of a hardened product, and ispreferably not more than 1.3, more preferably not more than 1.1, mostpreferably not more than 1.0.

Further, the slag composition (A) contains a total of 0.1 to 50 wt. % ofone or more compounds selected from the group consisting of iron oxide(in terms of Fe₂ O₃), alkali components (in terms of a total of Na₂ Oand K₂ O, a phosphorous component (in terms of P₂ O₅), titanium dioxide(in terms of TiO₂), manganese oxide (in terms of MnO), and magnesiumoxide (in terms of MgO) and/or 0.1 to 10 wt. % of a halogen component.Here, one or more compounds of iron oxide, alkali components,phosphorous components, titanium dioxide, manganese oxide, and magnesiumoxide may be contained in a total amount of 0.1 to 50 wt. %, but arepreferably contained in a total amount of 0.5 to 50 wt. %, particularlypreferably 5 to 50 wt. % in view of development of strength of ahardened product. One or more of these components may be contained in atotal amount of 0.1 to 50 wt. %, but preferably, contents of individualcomponents fall in the following ranges: iron oxide 0 to 20 wt. %, analkali component 0 to 30 wt. %, a phosphorous component 0 to 25 wt. %,titanium dioxide 0 to 20 wt. %, manganese oxide 0 to 10 wt. %, andmagnesium oxide 0 to 15 wt. %.

Iron oxide may be contained in an amount of 0 to 20 wt. %, but ispreferably contained in an amount of 0.5 to 20 wt. %. An alkalicomponent may be contained in an amount of 0 to 30 wt. %, but ispreferably contained in an amount of 0.1 to 20 wt. %, more preferably 1to 10 wt. %. A phosphorous component may be contained in an amount of 0to 25 wt. %, but is preferably contained in an amount of 0.5 to 10 wt.%. Titanium oxide may be contained in an amount of 0 to 20 wt. %, but ispreferably contained in an amount of 0.1 to 20 wt. %. Manganese oxidemay be contained in an amount of 0 to 10 wt. %, but is preferablycontained in an amount of 0.1 to 5 wt. %. Magnesium oxide may becontained in an amount of 0 to 15 wt. %, but is preferably contained inan amount of 1 to 10 wt. %.

Examples of the halogen include fluorine and chlorine, with fluorinebeing particularly preferred. Halogenous content is 0.1 to 10 wt. %,preferably 0.1 to 8 wt. %, particularly preferably 0.5 to 7.5 wt. %.

There may be contained either a halogen or one or more compoundsselected from the group consisting of iron oxide, alkali components,phosphorous components, titanium dioxide, manganese oxide, and magnesiumoxide, but both may be contained. Of course, when both are contained,their contents may fall in the above-described smaller ranges.

In addition to the above-described components, the slag composition (A)may also contain a small amount to a trace amount of B₂ O₃, SO₃, copperoxide, SnO₂, and ZnO₂.

As previously described, the fused slag produced from asludge-incinerated substance and the fused slag produced from arefuse-incinerated substance may not contain a Ca component. Fused slagwhich contains a very small amount of a Ca component or no Ca componentsis considered suitable for being mixed, particularly with portlandcement to make mixed cement.

In view of formation of a C-S-H hydrate, which is considered highlyeffective for development of strength, fused slag preferably contains aCa component.

Fused slag produced from a refuse-incinerated substance and fused slagproduced from a sludge-incinerated substance preferably contain a Cacomponent in an amount of 1 to 37 wt. % in terms of CaO, more preferably1 to 35 wt. %, most preferably 8 to 35 wt. %. Since fused slag producedfrom a refuse- or sludge-incinerated substance normally contains a largeamount of iron and alkali in distinction from blast furnace slag, evenwhen the CaO content exceeds 37 wt. %, the fused slag results inhardening material, but the resultant hardening material may be highlylikely to become a hard-to-vitrify composition due to a relatively lowcontent of silica and a phosphate component which are glass-formingoxides, or may become a quick-setting compound or a compound having poordevelopment of strength. Further, formation of fused slag generallyrequires high temperatures and thus requires much incineration energy.This accompanies an undesirable phenomenon that furnace material sharplybecomes susceptible to erosion as the furnace temperature increases. Insuch an event, mixing fused slag with portland cement is preferable inmany cases.

Of course, through adjustive addition of SiO₂, CaO, Al₂ O₃, etc., acomposition similar to a high-CaO type blast furnace slag compositioncan be obtained.

However, since a composition of the present invention can be a goodhardening composition and can provide a good hardened product withoutincreasing the CaO content, when material for slag is of a relativelyhigh CaO content and a relatively low SiO₂ content, SiO₂, for example,may be added to the material to thereby promote vitrification and toreduce the relative CaO content (1≧C/S). The thus-prepared material isslagged to thereby remedy the above-described problem. In this case,since there is a preferable aspect that the thus-produced slag absorbsalkali components and calcium hydroxide, a component having anunnecessarily high CaO content is rather not preferable.

A blast furnace slag having a CaO content of 40 wt. % or more is not sounique. According to studies on blast furnace slag-related compositionswhich had been conducted by many researchers, a blast furnace slagcomposition having a high activity of hydration and good development ofstrength is a 4-component composite slag composition composed of SiO₂,Al₂ O₃, CaO, and MgO, which are principal components of blast furnaceslag and are contained in the following composition: SiO₂ 31.28 wt. %,Al₂ O₃ 15.48 wt. %, CaO 49.08 wt. %, and Mgo 4.69 wt. %. As reported bythese researchers, blast furnace slag compositions having a high CaOcontent have a high activity of hydration. In actual blast furnace slagcompositions, it is known that when a CaO content reduces below about 35wt. %, its activity of reaction significantly decreases. By contrast, afused slag composition shows a high activity of reaction not only whenthe CaO content thereof is about 35 wt. %, but also when the CaO contentis as low as about 8 wt. % which is inconceivably low in view ofconventional sense of research, and further even when no CaO iscontained. This also indicates that fused slag of the present inventionis significantly different from conventional blast furnace slag. A fusedslag composition which contains 0 to 8 wt. % of CaO is preferably mixedwith portland cement serving as an alkaline activator to thereby be usedin the form of mixed cement.

For the above-described reason, the present invention limits a CaOcontent to the aforementioned range.

The above-described slag preferably contains an alumina component in anamount of 0 to 40 wt. %, particularly preferably 10 to 30 wt. %. Analumina content is limited to such a range because an alumina contentexceeding 40 wt. % causes a failure to obtain a hardened product havinggood development of hardness, and slagging requires very hightemperatures. Also, even when no alumina component is contained, ahardening composition is obtainable. This is another reason why analumina content is limited to the above-described range. When zeolite isto be generated through hydration of slag of the present invention,alumina is preferably contained to some extent, more preferably in anamount of 10 to 30 wt. %.

The silica content of a slag composition of the present invention is 23to 90 wt. %. When the silica content reduces below 23 wt. %, slagging(vitrification) becomes difficult to attain, and then reduces theproduction of calcium silicate hydrate which is indispensable to securedevelopment of strength, resulting in poor development of strength. Onthe contrary, when the silica content exceeds 90 wt. %, slagging(vitrification) requires high temperatures, resulting in difficulty inslagging.

The above-described fused slag preferably contains a P component.

Particularly, preferable are fused slag produced from asludge-incinerated substance and fused slag produced from a municipalrefuse-incinerated substance which contain a P component in an amount of0 to 25 wt. % (particularly 1 to 10 wt. %) in P₂ O₅. The content of a Pcomponent is limited to the above-described range because when thecontent of a P component exceeds 25 wt. %, the content of othercomponents effective for hardening and development of strengthrelatively reduces, resulting in the difficulty of obtaining a goodhardened product.

The above-described fused slag produced from a sludge-incineratedsubstance preferably contains Na and/or K components (alkalicomponents).

Particularly, preferable are fused slag produced from arefuse-incinerated substance and fused slag produced from asludge-incinerated substance which contain Na and K components in anamount of 0 to 30 wt. % in terms of a total of Na₂ O and K₂ O, morepreferably 0.1 to 30 wt. %, most preferably 1 to 10 wt. %. When thealkali content exceeds 30 wt. %, development of strength deteriorates,and an alkali component becomes more likely to be eluted from a hardenedproduct, resulting in deterioration of durability of the hardenedproduct. When a slag composition used in the present invention is mixedwith portland cement serving as an activator to thereby form so-calledmixed cement, a relatively high alkali content has an adverse effectparticularly on long-term strength. Thus, although balance with othercomponents must be considered, the alkali content of the slagcomposition is preferably not more than 10 wt. %.

Generally, the above-described fused slag produced from asludge-incinerated substance and like slag preferably contain an Fecomponent. Fused slag produced from a refuse-incinerated substance andfused slag produced from a sludge-incinerated substance preferablycontain an Fe component in an amount of 0 to 20 wt. % (particularly 0.5to 20 wt. %) in terms of Fe₂ O₃. An Fe component produces a good effectof making a glass structure unstable and decreasing a fusiontemperature, i.e. burning energy, but has a significantly adverse effecton development of strength when the content thereof exceeds 20 wt. %.

The above-described fused slag produced from a sludge-incineratedsubstance and like slag preferably contain an Mg component in an amountof 0 to 15 wt. % (particularly 1 to 10 wt. %) in terms of MgO. An Mgcomponent also produces a good effect of making a glass structureunstable to thereby activate slag, but has an adverse effect ondevelopment of strength when the content thereof exceeds 15 wt. %.

The above-described fused slag produced from a sludge-incineratedsubstance and like slag preferably contain a Ti component in an amountof 0 to 20 wt. % (particularly 0.1 to 20 wt. %) in terms of TiO₂. A Ticomponent also produces a good effect of making a glass structureunstable to thereby activate slag, but has an adverse effect ondevelopment of strength and economically produces an disadvantageouseffect when the content thereof exceeds 20 wt. %.

The above-described fused slag produced from a sludge-incineratedsubstance and like slag preferably contain an Mg component in an amountof 0 to 10 wt. % (particularly 0.1 to 5 wt. %) in terms of MnO. An Mgcomponent also produces a good effect of making a glass structureunstable to thereby activate slag, but has an adverse effect ondevelopment of strength and economically produces an disadvantageouseffect when the content thereof exceeds 10 wt. %.

The above-described fused slag produced from a sludge-incineratedsubstance and like slag preferably contains a halogen (fluorine andchlorine) in an amount of 0 to 10 wt. %, more preferably 0.1 to 8 wt. %,most preferably 0.5 to 7.5 wt. %. A halogen also produces a good effectof making a glass structure unstable to thereby activate slag, but hasan adverse effect on development of strength and economically producesan disadvantageous effect when the content thereof exceeds 10 wt. %.Examples of a halogen include fluorine, chlorine, bromine, etc., butgenerally fluorine is preferable because chlorine and bromine have theproperty of corroding reinforcing bars.

As previously described, the slag composition (A) used in the presentinvention is obtained by melting at high temperatures a mixture ofvarious materials which are mixed so as to attain the above-describedchemical composition, and quenching the resulting melt. The slagcomposition (A) can also be manufactured by slagging asludge-incinerated substance, a refuse-incinerated substance, orindustrial waste.

A sludge-incinerated substance is obtained by dehydrating sludge byvarious methods. Examples of a sludge-incinerated substance includelime-based sludge-incinerated ashes which are prepared using slaked limeor the like as a dehydration aid, and polymer-based sludge-incineratedashes which are prepared using polymeric flocculent as a dehydrationaid. An example of a refuse-incinerated substance is a normal municipalrefuse-incinerated substance. Industrial waste is waste other thanmunicipal refuse. Examples of industrial waste include crushed stonesludge and waste concrete.

A melting temperature for these materials is not particularly limited,but is normally preferably 1200° to 1600° C. Melting is conducted in,for example, an electric fusion furnace such as an arc type fusionfurnace, a plasma type fusion furnace, or an electric resistance typefusion furnace, or a gas- or like fuel-fired fusion furnace such as areverberatory type surface fusion furnace or a radiation type surfacefusion furnace. Examples of quenching means include water quenching andair quenching. Water quenching is particularly preferable.

When the thus-obtained slag composition (A) contains fused slag producedfrom a sludge-incinerated substance, fused slag produced from arefuse-incinerated substance, or fused slag produced from industrialwaste, it normally has the following composition: 5 to 35 wt. % of CaO,30 to 70 wt. % of SiO₂, 5 to 25 wt. % of Al₂ O₃, 2 to 20 wt. % of ironoxide, 1 to 15 wt. % of an alkali component, 0.5 to 23 wt. % of aphosphorous component, 0.1 to 3 wt. % of titanium dioxide, 0.1 to 3 wt.% of manganese oxide, 2 to 6 wt. % of magnesium oxide, 0 to 5 wt. % ofhalogens, and 0 to 5 wt. % of SO₃.

More specifically, in the case of fused slag produced from arefuse-incinerated substance which mainly comprises normally occurringrefuse-incinerated ashes, the contents of the above-described componentsare as follows: 7 to 35 wt. % of CaO, 30 to 70 wt. % of SiO₂, about 5 to22 wt. % of Al₂ O₃, 0.5 to 15 wt. % of Fe₂ O₃, 0.5 to 6 wt. % of MgO, 2to 15 wt. % of Na₂ O and K₂ O combined, 0.5 to 5 wt. % of P₂ O₅, about0.0 to 5 wt. % of halogens (chlorine, etc.), 0.0 to 5 wt. % of SO₃, 0.1to 3 wt. % of manganese oxide, 2 to 6 wt. % of magnesium oxide, about0.0 to 5 wt. % of halogens, 0.0 to 5 wt. % of SO₃, about 0.1 to 1 wt. %of MnO, and about 0.5 to 3 wt. % of TiO₂.

For fused slag produced from a sludge-incinerated substance, a CaOcontent falls in a range of about 5 to 35 wt. %. An SiO₂ content fallsin a range of about 20 to 45 wt. %, normally 25 to 40 wt. %. An Al₂ O₃content falls in a range of about 5 to 25 wt. %, normally 10 to 20 wt.%. An MgO content falls in a range of about 2 to 5 wt. %, normally about3 wt. % in many cases. For lime-based sludge-incinerated ashes, a P₂ O₅content falls in a range of about 1 to 10 wt. %, normally 5 to 10 wt. %;for polymer-based sludge-incinerated ashes, a P₂ O₅ content falls in arange of about 7 to 23 wt. %, normally 7 to 20 wt. %. Alkali contentfalls in a range of about 1 to 5 wt. % in terms of a total of Na₂ O andK₂ O, normally about 3 wt. % in many cases. An Fe content falls in arange of about 5 to 20 wt. % in terms of Fe₂ O₃, normally about 10 wt. %in many cases.

The shape of the slag composition (A) used in the present invention isnot particularly limited, but is preferably powdery, granular, or grain,more preferably powdery or granular depending on applications,percentage of use, mixing and forming conditions, etc. Particularly, thesurface area is preferably not less than 2000 cm² /g in Blaine value, orthe grain size of powder is preferably 0.1 to 5 mm.

An alkaline activator used in the present invention is one or morecompounds selected from the group consisting of alkali metal hydroxides,alkaline earth metal hydroxides, and weak-acid alkaline metal salts.Examples of alkaline metal hydroxides include NaOH, KOH, and LiOH.Examples of alkaline earth metal hydroxides include Ca(OH)₂ and Mg(OH)₂.Examples of weak-acid alkaline metal salts include sodium carbonate,potassium carbonate, sodium silicate, potassium silicate, sodiumaluminate, and potassium aluminate. Also, since portland cement containsa small amount of alkali silicate and aluminosilicate and producesCa(OH)₂ through hydration thereof, it can be an alkaline activator.Here, portland cement is not limited to normal portland cement, but canbe of an early-strength type and a low heat-generation type.

In the present invention, an appropriate mixing ratio between the slagcomposition (A) and the alkaline activator (B) varies depending on thechemical composition of slag and is not particularly limited. Forexample, the ratio between the slag composition (A) and an alkalineactivator is preferably as follows: 0.01 to 10 parts by weight of analkaline activator to 100 parts by weight of the slag composition (A)when an alkaline metal compound is used as an alkaline activator; and 3to 100 parts by weight of an alkaline activator to 100 parts by weightof the slag composition (A) when an alkaline earth metal compound isused as an alkaline activator.

Since portland cement itself is a source of alkali and calciumhydroxide, when a portland cement composition is used as an alkalineactivator, portland cement can be considered as a combination of theabove-described alkaline activator and an alkaline earth metal compound.Further, since portland cement itself has a setting property, there isno upper limitation to the amount of portland cement used to obtain ahardened product, i.e. portland cement can be mixed in a large amount.However, since a mixture of the slag composition (A) of the presentinvention and portland cement is a so-called mixed cement composition,they are preferably mixed at the following general ratio: about 0.1 to60 parts by weight of the slag composition (A) to 100 parts by weight ofportland cement.

A hardening composition of the present invention may also containmaterials other than the above-described slag composition (A) and thealkaline activator (B). Examples of such materials include So₃, blastfurnace slag, and fly ash.

As previously described, a hardening composition of the presentinvention has good hydraulicity, it can be formed into a hardenedproduct having excellent strength merely through mixture with water.Specifically, the aforementioned hardening composition is mixed withwater, and the resulting mixture is cured to set, obtaining a hardenedproduct having excellent strength. Also, the aforementioned hardeningcomposition is mixed with water and aggregate, and the resulting mixtureis cured to harden, obtaining a hardened product. Curing conditions arenot particularly limited, but curing is preferably performed at atemperature of 60° to 80° C. for 4 to 24 hours. Like portland cement,slag of a properly prepared composition may also be cured at roomtemperature to obtain a good hardened product. Applicable aggregateincludes not only slag of the present invention but also aggregate foruse in normal concrete, mortar, block products, and constructionmaterials. Examples of such aggregate include sand, gravel, crushedstone, and lightweight aggregate.

A detailed scientific illumination of why a mixture of fused slagproduced from a sludge-incinerated substance or fused slag produced froma municipal refuse-incinerated substance and an alkaline activator(including portland cement) hardens is left to a future study. Thepresent inventor analyzed the reason as follows.

Fused slag produced from a sludge-incinerated substance and fused slagproduced from a municipal refuse-incinerated substance are rich in notonly SiO₂, which is a glass-forming oxide, but also Al₂ O₃ and CaO andfurther iron components (Fe₂ O₃, etc.), MgO, alkalis (Na₂ O, K₂ O), aphosphorous component (P₂ O₅), and also contain a sulfur (S) component,a manganese component, and TiO₂. Further, municipal refuse-incineratedashes contain a halogen (particularly chlorine, Cl).

That is, not only a quantitative relation among a silica component, acalcium component, an alumina component, and a magnesium component,which are principal components of blast furnace slag, but also an ironcomponent, a phosphorous component (P₂ O₅), an alkali component,manganese, etc., which are rarely or very slightly contained in blastfurnace slag, have a great effect on reactivity of fused slag producedfrom a sludge-incinerated substance and fused slag produced frommunicipal refuse-incinerated substance. Alkali, an iron component, aphosphorous component, and halogens (chlorine, fluorine, etc.) areparticularly influential.

Since fused slag produced from a sludge-incinerated substance and fusedslag produced from a municipal refuse-incinerated substance aresubstantially glass, the glass structure of fused slag produced from asludge-incinerated substance and fused slag produced from a municipalrefuse-incinerated substance is made unstable through disturbance orpartial cutting of the glass structure of silica (SiO₂), which is aglass-forming oxide. As a result, the glass structure becomessusceptible to erosion particularly in an alkaline environment.Components which are eluted through erosion hydrate with, for example,calcium hydroxide which is generated through hydration of portlandcement, thereby forming compounds such as zeolite which is a compound ofcalcium silicate hydrate (C--S--H), alkali (calcium)-alumina-silica,etc. Thus, strength is developed.

That is, the glass structure of fused slag produced from asludge-incinerated substance is considered to have, for example, a chainstructure represented by --Si--O--Fe--O--Si--O--Al--O--P--O-- formedthrough coupling of silica with alumina, iron, phosphoric acid, etc.Fused slag produced from a sludge-incinerated substance contains lessSiO₂ than normal soda-lime-based glass and aluminosilicate glass, andthus the glass structure thereof is likely to become unstable. Moreover,fused slag produced from a sludge-incinerated substance contains notonly modifier oxides such as Na₂ O, K₂ O, calcium oxide (CaO), alumina(Al₂ O₃), and magnesium oxide (MgO) which are contained in normalsoda-lime-based glass and aluminosilicate glass, but also ironcomponents (Fe₂ O₃ and FeS), a phosphorous component (P₂ O₅), manganeseoxide (MnO), sulfur (S), and titania (TiO₂), which are rarely or notmuch contained in normal glass and which are considered to further makethe glass structure unstable. Like glass which contains, for example, aphosphorous component (P₂ O₅) is known to be unstable and susceptible toalkali and water, once a phosphorous component (P₂ O₅), alkalis, iron,calcia, magnesia, and alumina, etc. enter the glass structure, theyproduce a composite effect of making the glass structure unstable. As aresult, the structure of the coupling chain of silica, which is aglass-forming oxide, is further disturbed to deform or partially break.Thus, the glass structure is in an unstable state which is not observedwith the normal glass structure such as the structure of window glass,i.e. the glass structure is in an "activated, highly reactive" state.However, in the case of a phosphorous component, addition of alumina tophosphate glass further stabilizes the glass structure for a certainregion. Therefore, alkali components, iron, etc. are considered toproduce a relatively high composite effect of making the glass structureunstable.

When fused slag in such an unstable glass state is combined with alkalimaterials such as alkali hydroxide, soda silicate (water glass),portland cement, etc., the slag readily erodes, and consequently ionsand compounds of slag components such as Si, Al, Mg, Fe, and P areeluted to form hydrates. Thus, the mixture hardens. This is a hardeningmechanism that the inventor conjectures.

For example, when water is added to a mixture of the aforementioned slagcomposition and portland cement which has been widely used as cementconcrete material, there are formed insoluble compounds such as calciumsilicate hydrate (C--S--H), zeolite, etc., which are formed throughhydration between calcium hydroxide generated through hydration ofportland cement and silica, alumina, etc. from the slag composition.Thus, the mixture hardens.

A composition which forms silicate compounds such as zeolite, which arehydrate compounds of alkali components, alumina, silica, etc., isconsidered to be slag having a CaO/SiO₂ mole-ratio (C/S) of below about1.2. As the C/S ratio increases, formation of aluminate compounds maybecome dominant as observed with blast furnace slag.

That is, the hydration of normal blast furnace slag (normally C/S>1.3)with blast furnace cement, which is mixed cement of portland cement andblast furnace slag, is known to produce the above-described calciumsilicate hydrate (C--S--H), calcium sulfoaluminate hydrate, calciumaluminate hydrate, etc. For fused slag produced from asludge-incinerated substance and fused slag produced from a municipalrefuse-incinerated substance, the ratio between calcium (C) and silica(S) (C/S mole-ratio) is generally lower than that of blast furnace slag(mostly C/S≧1.3), normally not more than about 1.15, mostly not morethan 1. Accordingly, calcium is too short to produce a calcium aluminatehydrate, and thus silicate compounds such as zeolite are formed.

However, for fused slag produced from a lime-based sludge-incineratedsubstance, which is prepared using lime as a dehydrator, the C/S ratioexceeds 1.2 in some cases. In such a case, like blast furnace slag,calcium aluminate hydrate may be formed, resulting in likelihood of poorsurface hardening, which is a drawback of blast furnace slag. Thus, whenthe alumina content of a slag composition is relatively high, usingalkali silicate having a silica source, such as soda silicate, as astimulator may prevent formation of an aluminate-based hydrate and maybring formation of silicate compounds. In this case, alkali silicatesuch as water glass rather than alkali hydroxide is suited to be analkaline activator. However, when the C/S ratio is excessively high,fused slag, together with portland cement, may be used in the form ofmixed cement.

When fused slag produced from a sludge-incinerated substance or fusedslag produced from a municipal refuse-incinerated substance having arelatively low C/S ratio is used with portland cement serving as anactivator particularly when used in the form of mixed cement, a calciumcontent is too low to produce calcium aluminate hydrate. This has beenconfirmed through X-ray analysis of hydrate. It has also been confirmedthat calcium hydroxide is hardly produced (hardly remains) for a certainusage of fused slag.

For a composition having a low C/S ratio, a zeolite compound is likelyto be produced. Thus, there is an extreme case where such a compositionhardly hardens when the usage of an alkaline activator such as NaOH istoo small, due to absorption of entire alkalis, but shows a gooddevelopment of strength when the usage of an activator is increased. Itis therefore apparent that a hardening composition of the presentinvention has a high capability of absorbing and fixing NaOH, Ca(OH)₂,etc.

Thus, for example, by mixing a hardening composition of the presentinvention with an appropriate amount of portland cement serving as analkaline activator, there can be formed a hardened product in which theproduction of calcium hydroxide is suppressed or even prevented.Accordingly, this mixture has a potential for solving the problems ofefflorescence and alkali-aggregate reaction which are observed with aconventional portland cement-hardened product. Further, since themixture reactively absorbs alkali components, which have an adverseeffect on glass fiber, and also reactively absorbs calcium hydroxide tothereby reduce or prevent the production of calcium hydroxide, themixture can be used as cement for glass fiber reinforced concreteproducts. As compared with conventional portland cement, the mixtureprovides a hardened product having excellent acid resistance and seawater resistance, and thus has a potential for application to structureswhich are required to be corrosion resistant, such as marine structuresand sewer pipes.

A specific hardening mechanism is still unknown, but in distinction fromblast furnace slag, even a slag composition which contains very littleor no CaO provides a hardening composition which provides gooddevelopment of strength, through combined use of the slag combinationwith an alkaline stimulator such as alkali hydroxide, alkali silicate,portland cement, or the like.

EXAMPLES

The present invention will next be described by way of example, whichshould not be construed as limiting the invention. Examples 1--1 to 1-64and Comparative Examples 1--1 to 1-11:

A sample was prepared so as to have a composition shown in Tables 1 to5, using special grade chemicals from Kanto Kagaku Co., Ltd. Thethus-prepared sample was melted by heating at a temperature of 1200° to1500° C. for 60 minutes and at a temperature of 1250° to 1550° C. for 60minutes. When a melt had too high a viscosity to flow out or whenvitrification seemed to be insufficient, additional heating wasperformed at a temperature of 1300° to 1580° C. for 10 to 20 minutes.Subsequently, the resulting melt was led into water to be quenched,thereby obtaining fused slag.

The thus-obtained fused slag was pulverized in a ball mill to a finenessof 3000 cm² /g and 4500 cm² /g in Blaine value. To 85 parts by weight ofthe thus-pulverized material, were added 255 parts by weight of standardsand to be used in an ISO mortar strength test, sodium hydroxide as analkaline activator in an amount shown in Tables 1 to 5, and 42.5 partsby weight of water. The resultant mixture was mixed in a Hobart mixer.The mixed mixture was charged into a mold for forming a sample having asize of 2 cm×2 cm×8 cm to be used in a strength test, while vibrationwas applied to the frame.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 50° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 12 hours (curing time), therebyobtaining a sample.

Tables 1 to 4 show measurements of compressive strength for each of thethus-obtained samples.

                                      TABLE 1                                     __________________________________________________________________________                                            Compressive                                                                   strength                                                                 Amount                                                                             (kgf/cm.sup.2)                        Composition of fused slag (wt. %)  of NaOH                                                                            Curing                                                                C/S                                                                              added                                                                              time 12                               SiO.sub.2                                                                              CaO                                                                              Al.sub.2 O.sub.3                                                                  Fe.sub.2 O.sub.3                                                                  MgO                                                                              Na.sub.2 O                                                                       P.sub.2 O.sub.5                                                                  F  ratio                                                                            (wt. %)                                                                            hours                                 __________________________________________________________________________    C. Ex. 1-1                                                                          39.2                                                                             45.8                                                                             15  0   0  0  0  0  1.25                                                                             3    81.5                                  C. Ex. 1-2                                                                          39.2                                                                             45.8                                                                             15  0   0  0  0  0  1.25                                                                             7    131                                   C. Ex. 1-3                                                                          44.0                                                                             41.0                                                                             15  0   0  0  0  0  1.00                                                                             3    65.9                                  C. Ex. 1-4                                                                          50.0                                                                             35.0                                                                             15  0   0  0  0  0  0.75                                                                             3    133.5                                 C. Ex. 1-5                                                                          50.0                                                                             35.0                                                                             15  0   0  0  0  0  0.75                                                                             7    138.1                                 C. Ex. 1-6                                                                          50.0                                                                             35.0                                                                             15  0   0  0  0  0  0.75                                                                             10   129.5                                 C. Ex. 1-7                                                                          58.0                                                                             27.0                                                                             15  0   0  0  0  0  0.50                                                                             3    150.5                                 C. Ex. 1-8                                                                          58.0                                                                             27.0                                                                             15  0   0  0  0  0  0.50                                                                             7    130.4                                 C. Ex. 1-9                                                                          68.9                                                                             16.1                                                                             15  0   0  0  0  0  0.25                                                                             3    33.5                                  Ex. 1-1                                                                             39.5                                                                             45.0                                                                             15  0   0  0  0  0.5                                                                              1.25                                                                             3    148.4                                 Ex. 1-2                                                                             36.9                                                                             43.1                                                                             15  0   0  0  0  5.0                                                                              1.25                                                                             3    283.1                                 Ex. 1-3                                                                             35.8                                                                             41.7                                                                             15  0   0  0  0  7.5                                                                              1.25                                                                             3    183.2                                 Ex. 1-4                                                                             49.9                                                                             35.0                                                                             15  0   0  0  0  0.1                                                                              0.75                                                                             7    183.3                                 Ex. 1-5                                                                             49.4                                                                             34.6                                                                             15  0   0  0  0  1  0.75                                                                             7    506.8                                 Ex. 1-6                                                                             47.1                                                                             32.9                                                                             15  0   0  0  0  5  0.75                                                                             7    285.6                                 Ex. 1-7                                                                             44.1                                                                             30.9                                                                             15  0   0  0  0  10 0.75                                                                             15   140.1                                 Ex. 1-8                                                                             49.4                                                                             34.6                                                                             15  1   0  0  0  0  0.75                                                                             3    188.5                                 Ex. 1-9                                                                             47.1                                                                             32.9                                                                             15  5   0  0  0  0  0.75                                                                             3    160.7                                 Ex. 1-10                                                                            44.1                                                                             30.9                                                                             15  10  0  0  0  0  0.75                                                                             7    146.2                                 Ex. 1-11                                                                            38.2                                                                             26.8                                                                             15  20  0  0  0  0  0.75                                                                             10   233.1                                 C. Ex. 1-10                                                                         32.4                                                                             22.6                                                                             15  30  0  0  0  0  0.75                                                                             10   33.6                                  Ex. 1-12                                                                            49.4                                                                             34.6                                                                             15  0   1  0  0  0  0.75                                                                             3    174.7                                 Ex. 1-13                                                                            47.1                                                                             32.9                                                                             15  0   5  0  0  0  0.75                                                                             3    170.3                                 Ex. 1-14                                                                            44.1                                                                             30.9                                                                             15  0   10 0  0  0  0.75                                                                             3    161.0                                 __________________________________________________________________________     Note) C. Ex.: Comparative Example                                        

                                      TABLE 2                                     __________________________________________________________________________    Ex. 1-15                                                                            41.2                                                                             28.8                                                                             15  0   15 0  0  0  0.75                                                                             3    146.2                                 C. Ex. 1-11                                                                         38.2                                                                             26.8                                                                             15  0   20 0  0  0  0.75                                                                             3    116.3                                 Ex. 1-16                                                                            49.9                                                                             35.0                                                                             15  0   0  0.1                                                                              0  0  0.75                                                                             3    144.1                                 Ex. 1-17                                                                            49.9                                                                             34.6                                                                             15  0   0  1  0  0  0.75                                                                             7    183.2                                 Ex. 1-18                                                                            47.1                                                                             32.9                                                                             15  0   0  5  0  0  0.75                                                                             3    167.4                                 Ex. 1-19                                                                            44.1                                                                             30.9                                                                             15  0   0  10 0  0  0.75                                                                             3    176.9                                 Ex. 1-20                                                                            38.2                                                                             26.8                                                                             15  0   0  20 0  0  0.75                                                                             3    198.0                                 Ex. 1-21                                                                            32.4                                                                             22.6                                                                             15  0   0  30 0  0  0.75                                                                             3    246.8                                 Ex. 1-22                                                                            44.1                                                                             30.9                                                                             15  0   5  5  0  0  0.75                                                                             3    175                                   Ex. 1-23                                                                            43.5                                                                             30.5                                                                             15  0   5  5  1  0  0.75                                                                             7    173                                   Ex. 1-24                                                                            41.2                                                                             28.8                                                                             15  0   5  5  5  0  0.75                                                                             3    246.8                                 Ex. 1-25                                                                            38.2                                                                             26.8                                                                             15  0   5  5  10 0  0.75                                                                             3    237.8                                 Ex. 1-26                                                                            48.2                                                                             33.8                                                                             15  1   0  1  1  0  0.75                                                                             3    208                                   Ex. 1-27                                                                            48.2                                                                             33.8                                                                             15  1   0  1  1  0  0.75                                                                             3    169                                   Ex. 1-28                                                                            45.3                                                                             31.7                                                                             15  1   5  1  1  0  0.75                                                                             3    179.6                                 Ex. 1-29                                                                            45.3                                                                             31.7                                                                             15  1   5  1  1  0  0.75                                                                             7    169                                   Ex. 1-30                                                                            45.9                                                                             32.1                                                                             15  1   5  1  0  0  0.75                                                                             3    160.8                                 Ex. 1-31                                                                            45.9                                                                             32.1                                                                             15  1   5  0  1  0  0.75                                                                             3    160.2                                 Ex. 1-32                                                                            45.9                                                                             32.1                                                                             15  0   5  1  1  0  0.75                                                                             3    172.7                                 Ex. 1-33                                                                            36.2                                                                             33.8                                                                             10  5   5  5  2.5                                                                              2.5                                                                              1.00                                                                             3    434.3                                 Ex. 1-34                                                                            33.6                                                                             31.4                                                                             15  5   5  5  2.5                                                                              2.5                                                                              1.00                                                                             3    338.0                                 Ex. 1-35                                                                            31.0                                                                             29.0                                                                             20  5   5  5  2.5                                                                              2.5                                                                              1.00                                                                             3    264.7                                 Ex. 1-36                                                                            50.0                                                                             35.0                                                                             0   0   5  5  5  0  0.75                                                                             3    287.8                                 Ex. 1-37                                                                            41.2                                                                             28.8                                                                             15  0   5  5  5  0  0.75                                                                             3    246.8                                 Ex. 1-38                                                                            29.4                                                                             20.6                                                                             30  0   5  10 5  0  0.75                                                                             10   287.8                                 __________________________________________________________________________

                                      TABLE 3                                     __________________________________________________________________________    Ex. 1-39                                                                            36.8                                                                             25.7                                                                             15  5   5  10 0  2.5                                                                              0.75                                                                             1    224.7                                 Ex. 1-40                                                                            36.8                                                                             25.7                                                                             15  5   5  10 0  5  0.5                                                                              3    480.3                                 Ex. 1-41                                                                            44.5                                                                             30.9                                                                             10  5   5  5  0  0  0.75                                                                             3    308.4                                 Ex. 1-42                                                                            41.2                                                                             28.8                                                                             15  5   5  5  0  0  0.75                                                                             3    162.1                                 Ex. 1-43                                                                            47.1                                                                             32.9                                                                             0   5   5  5  5  0  0.75                                                                             3    227.4                                 Ex. 1-44                                                                            38.2                                                                             26.8                                                                             15  5   5  5  5  0  0.75                                                                             3    251.2                                 Ex. 1-45                                                                            35.3                                                                             24.7                                                                             20  5   5  5  5  0  0.75                                                                             3    195.4                                 Ex. 1-46                                                                            48.5                                                                             34.0                                                                             0   5   5  5  0  2.5                                                                              0.75                                                                             3    243.5                                 Ex. 1-47                                                                            42.6                                                                             29.9                                                                             10  5   5  5  0  2.5                                                                              0.75                                                                             3    368.1                                 Ex. 1-48                                                                            39.7                                                                             27.8                                                                             15  10  5  5  0  2.5                                                                              0.75                                                                             3    387.6                                 Ex. 1-49                                                                            36.8                                                                             25.7                                                                             20  5   5  5  0  2.5                                                                              0.75                                                                             3    302.3                                 Ex. 1-50                                                                            25.0                                                                             17.5                                                                             40  5   5  5  0  2.5                                                                              0.75                                                                             7    183.2                                 Ex. 1-51                                                                            25.0                                                                             17.5                                                                             40  5   5  5  0  2.5                                                                              0.75                                                                             10   296.7                                 Ex. 1-52                                                                            47.1                                                                             32.9                                                                             0   5   5  5  2.5                                                                              2.5                                                                              0.75                                                                             3    198.2                                 Ex. 1-53                                                                            41.2                                                                             28.8                                                                             10  5   5  5  2.5                                                                              2.5                                                                              0.75                                                                             3    291.2                                 Ex. 1-54                                                                            38.2                                                                             26.8                                                                             15  5   5  5  2.5                                                                              2.5                                                                              0.75                                                                             3    305.2                                 Ex. 1-55                                                                            35.3                                                                             24.7                                                                             20  5   5  5  2.5                                                                              2.5                                                                              0.75                                                                             3    176.3                                 Ex. 1-56                                                                            44.3                                                                             20.7                                                                             15  5   5  5  2.5                                                                              2.5                                                                              0.50                                                                             3    214.8                                 Ex. 1-57                                                                            34.1                                                                             15.9                                                                             30  5   5  5  2.5                                                                              2.5                                                                              0.50                                                                             7    332.0                                 Ex. 1-58                                                                            32.4                                                                              7.6                                                                             40  5   5  5  2.5                                                                              2.5                                                                              0.25                                                                             10   221.9                                 __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________                                     Compressive                                                                   strength                                     Composition of fused slag  Amount                                                                              (kgf/cm.sup.2)                               (wt. %)                    of NaOH                                                                             Curing                                                               C/S                                                                              added time 12                                      SiO.sub.2                                                                              CaO                                                                              Al.sub.2 O.sub.3                                                                   TiO.sub.2                                                                        MnO ratio                                                                            (wt. %)                                                                             hours                                        __________________________________________________________________________    Ex. 1-59                                                                           47.1                                                                              32.9                                                                             15   5  0   0.75                                                                             3     224.3                                        Ex. 1-60                                                                           44.1                                                                              30.9                                                                             15   10 0   0.75                                                                             10    495.5                                        Ex. 1-61                                                                           38.2                                                                              26.8                                                                             15   20 0   0.75                                                                             10    362.0                                        Ex. 1-62                                                                           38.2                                                                              26.8                                                                             15   20 0   0.75                                                                             15    358.4                                        Ex. 1-63                                                                           47.1                                                                              32.9                                                                             15   0  5   0.75                                                                             3     151.9                                        Ex. 1-64                                                                           44.1                                                                              30.9                                                                             15   0  10  0.75                                                                             10    144                                          __________________________________________________________________________

As seen from Tables 1 to 4, hardening compositions of the presentinvention which contained the slag composition (A) that satisfied theaforementioned conditions and the alkaline activator (B) providedhardened products having excellent strength merely by adding waterthereto and mixing and curing the resultant mixture.

Example 2-1

Lime-based sludge slag (material from Osaka Municipal Sewerage Corp.having the following major chemical composition (wt. %): SiO₂ 32.1, Al₂O₃ 14.1, Fe₂ O₃ 4.5, CaO 34.4, MgO 2.4, P₂ O₅ 8.0, S 1.2, Na₂ O 0.80, K₂O 0.51, and others) was pulverized in 200 g portions in a disk mill for10 minutes such that about 9 wt. % of residue was left on a 90 μm sieveand about 23 wt. % of residue was left on a 63 μm sieve. To 1600 partsby weight of the thus-pulverized material, were added 16 parts by weightof sodium hydroxide as an alkaline activator and 264 parts by weight ofwater. The resultant mixture was mixed in a Hobart mixer. The mixedmixture was charged into a mold for forming a sample having a size of 4cm×4 cm×16 cm to be used in a strength test of normal portland cementmortar, while vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 50° C.Subsequently, the temperature of the chamber was raised from 50° C. to80° C. over about 20 minutes at a relative humidity of 98%, andsubsequently the chamber was maintained at 80° C. for 2 hours (and 4hours) (curing time), thereby obtaining a sample.

Example 2-2

The pulverized material of lime-based sludge slag of Example 2-1 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 1 except that the amount of NaOH was 48parts by weight, thereby obtaining samples of 1-hour, 2-hour, 4-hour,and 22-hour curing at 80° C.

Example 2-3

The pulverized material of lime-based sludge slag of Example 2-1 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 1 except that the amount of NaOH was 48parts by weight and the amount of mixing water was 224 parts by weight,thereby obtaining samples of 1-hour, 2-hour, 4-hour, and 22-hour curingat 80° C.

Example 2-4

The pulverized material of lime-based sludge slag of Example 2-1 wasused to prepare a sample in a manner similar to that of Example 1 exceptthat the amount of NaOH was 48 parts by weight and curing was conductedin a humid environment at a temperature of 20° C. for 1 day (and 3days).

Example 2-5

The pulverized material of lime-based sludge slag of Example 2-1 wasused to prepare a sample in a manner similar to that of Example 1 exceptthat the amount of NaOH was 80 parts by weight and curing was conductedin a humid environment at a temperature of 20° C. for 1 day (and 3days).

Example 2-6

Five (5) kinds of test materials were prepared in a manner similar tothat of Examples 2-1 to 2-5 except that Ca(OH)₂ (first class gradechemical manufactured by Kanto Kagaku Co., Ltd.) in place of NaOH wasused in an amount of 48 parts by weight, 160 parts by weight, 240 partsby weight, and 320 parts by weight, water was used in an amount of 264parts by weight, 288 parts by weight, 335 parts by weight, and 352 partsby weight, respectively, and except that 1000 parts by weight of calciumhydroxide and 880 parts by weight of water were used with 1000 parts byweight of the pulverized material of sludge slag. Samples were obtainedfrom the thus-prepared 5 kinds of test materials in a manner similar tothat of Example 2-1. Curing time at 80° C. was 4 hours for all thesamples.

Example 2-7

713 parts by weight of the pulverized material of lime-based sludge slagof Example 2-1, 1147 parts by weight of aggregate prepared by coarselypulverizing the sludge slag to a grain size of 0.5 to 2.5 mm, 21.4 partsby weight of NaOH, and 168 parts by weight of water were mixed.Subsequently, a sample was obtained from the mixed mixture in a mannersimilar to that of Example 2-1. Curing time at 80° C. was 4 hours.

Example 2-8

The pulverized material of lime-based sludge slag of Example 2-1 wasmixed and cured in a manner similar to that of Example 2 (except thatcuring time at 80° C. was 18 hours). The resultant hardened product wascrushed. Subsequently, the crushed material was dried at a temperatureof 110° C. for 1 day. Then, 200 g of the crushed material was pulverizedin a disk mill for 3 minutes (residue on a 90 μm sieve: 14.6 wt. %). To1200 parts by weight of the thus-pulverized material, was added 228parts by weight of water. The resultant mixture was mixed in a Hobartmixer. Subsequently, a sample was obtained in a manner similar to thatof Example 2-1 through 4-hour curing at a temperature of 80° C.

Example 2-9

The pulverized material of lime-based sludge slag of Example 2-1 wasmixed and cured in a manner similar to that of Example 8 (except thatcuring time at 80° C. was 18 hours). The resultant hardened product wascrushed. Subsequently, the crushed material was dried at a temperatureof 110° C. for 1 day. Then, 200 g of the crushed material was pulverizedin a disk mill for 10 minutes (residue on a 90 μm sieve: 12 wt. %). To1700 parts by weight of the thus-pulverized material, was added 34 partsby weight of NaOH and 280.5 wt. % of water. The resultant mixture wasmixed in a Hobart mixer. Subsequently, a sample was obtained in a mannersimilar to that of Example 1 through 4-hour curing at a temperature of80° C.

Example 2-10

100 parts by weight of the pulverized material of lime-based sludge slagof Example 2-1 were placed in each of a plurality of beakers. Lithiumcarbonate, sodium carbonate, potassium carbonate, lithium hydroxide,potassium hydroxide, water glass No. 1, water glass No. 3, potassiumsilicate solution, and sodium aluminate solution were added in an amountof 5 parts by weight each as an alkaline activator into correspondingbeakers. Then, 18 parts by weight of water was added into each beaker.The resultant mixtures were mixed. These beakers were left for 4 to 8hours in a high-temperature high-humidity chamber which was regulated tomaintain a humid environment of 80° C. and 98%, thereby obtainingsamples.

The mixtures in these beakers all hardened.

Example 2-11

Polymer-based sludge-incinerated ashes were melted in an electricfurnace at a temperature of 1400° C. for 1 hour. The resultant melt waspoured into water to obtain vitric polymer-based sludge slag (materialfrom Tokyo Metropolitan *Government, Sewage Works Bureau, having thefollowing major chemical composition (wt. %): SiO₂ 35.1, Al₂ O₃ 18.6,Fe₂ O₃ 9.7, CaO 11.8, MgO 3.1 g, P₂ O₅ 14.1, S 0.04, Na₂ O 1.37, K₂ O2.69, MnO 0.35, and others). This sludge slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 9 wt. % ofresidue was left on a 90 μm sieve. To 150 parts by weight of thethus-pulverized material, were added 4.5 parts by weight of sodiumhydroxide as an alkaline activator and 45 parts by weight of water,followed by mixing. The mixed mixture was charged into a mold forforming a sample having a size of 2 cm×2 cm×8 cm while vibration wasapplied to the mold. The charged mold was placed in athermostat-hygrostat chamber from Tabai which was set to a temperatureof 50° C. Subsequently, the temperature of the chamber was raised from50° C. to 80° C. over about 20 minutes at a relative humidity of 98%,and subsequently the chamber was maintained at 80° C. for 4 hours(curing time), thereby obtaining a sample.

Example 2-12

To 150 g parts by weight of the pulverized material of polymer-basedsludge slag of Example 2-11, were added 37.5 parts by weight of calciumhydroxide as an alkaline activator and 45 parts by weight of water,followed by mixing. The mixed mixture was charged into a mold forforming a sample having a size of 2 cm×2 cm×8 cm while vibration wasapplied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber from Tabaiwhich was set to a temperature of 50° C. Subsequently, the temperatureof the chamber was raised from 50° C. to 80° C. over about 20 minutes ata relative humidity of 98%, and subsequently the chamber was maintainedat 80° C. for 4 hours (curing time), thereby obtaining a sample.

Example 2-13

To 150 g parts by weight of the pulverized material of polymer-basedsludge slag of Example 2-11, were added 4.5 parts by weight of calciumhydroxide as an alkaline activator, 37.5 parts by weight of calciumhydroxide, and 45 parts by weight of water, followed by mixing.

Since this mixed mixture shows a characteristic of setting in a shortperiod of time, water was further added up to 80 parts by weight,followed by forced mixing. The resultant mixed mixture was charged intoa mold for forming a sample having a size of 2 cm×2 cm×8 cm whilevibration was applied to the mold.

This formed object was placed in a thermostat-hygrostat chamber fromTabai which was set to a temperature of 20° C. and was left therein at arelative humidity of 98% for 1 day (curing time), thereby obtaining asample.

Example 2-14

To 150 g parts by weight of the pulverized material of polymer-basedsludge slag of Example 2-11, were added 0.38 parts by weight of sodiumhydroxide as an alkaline activator, 37.5 parts by weight of calciumhydroxide, and 45 parts by weight of water, followed by mixing. Themixed mixture was charged into a mold for forming a sample having a sizeof 2 cm×2 cm×8 cm while vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber from Tabaiwhich was set to a temperature of 50° C. Subsequently, the temperatureof the chamber was raised from 50° C. to 80° C. over about 20 minutes ata relative humidity of 98%, and subsequently the chamber was maintainedat 80° C. for 4 hours (curing time), thereby obtaining a sample.

Example 2-15

To 150 g parts by weight of the pulverized material of polymer-basedsludge slag of Example 2-11, were added 0.75 parts by weight of sodiumhydroxide as an alkaline activator, 37.5 parts by weight of calciumhydroxide, and 45 parts by weight of water, followed by mixing. Themixed mixture was charged into a mold for forming a sample measuring 2cm×2 cm×8 cm while vibration was applied to the mold. The charged moldwas placed in a thermostat-hygrostat chamber from Tabai which was set toa temperature of 50° C. Subsequently, the temperature of the chamber wasraised from 50° C. to 80° C. over about 20 minutes at a relativehumidity of 98%, and subsequently the chamber was maintained at 80C for4 hours (curing time), thereby obtaining a sample.

Example 2-16

A mixture of 70 parts by weight of polymer-based sludge-incineratedashes of Example 2-11 and 30 parts by weight of Ca(OH)₂ (first classgrade chemical manufactured by Kanto Kagaku Co., Ltd.) was melted in anelectric furnace at a temperature of 1450° C. for 1 hour. The resultantmelt was poured into water to obtain vitric polymer-based sludge slag.This sludge slag was pulverized in 200 g portions in a disk mill for 10minutes such that about 8 wt. % of residue was left on a 90 μm sieve. To150 parts by weight of the thus-pulverized material, were added 4.5parts by weight of sodium hydroxide as an alkaline activator and 27parts by weight of water, followed by mixing. The mixed mixture wascharged into a mold for forming a sample having a size of 2 cm×2 cm×8 cmwhile vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber from Tabaiwhich was set to a temperature of 50° C. Subsequently, the temperatureof the chamber was raised from 50° C. to 80° C. over about 20 minutes ata relative humidity of 98%, and subsequently the chamber was maintainedat 80° C. for 4 hours (curing time), thereby obtaining a sample.

Example 2-17

A mixture of 70 parts by weight of polymer-based sludge-incineratedashes of Example 2-11, 20 parts by weight of Ca(OH)₂ (first class gradechemical manufactured by Kanto Kagaku Co., Ltd.), and 10 parts by weightof crushed stone sludge (material from Yukou Kogyo Co., Ltd. having thefollowing major chemical composition (wt. %): SiO₂ 54.4, Al₂ O₃ 18.6,Fe₂ O₃ 6.2, CaO 5.6, MgO 2.8, Na₂ O 3.08, K₂ O 1.67, and others) wasmelted in an electric furnace at a temperature of 1400° C. for 1 hour.The resultant melt was poured into water to obtain vitric polymer-basedsludge slag. This sludge slag was pulverized in 200 g portions in a diskmill for 10 minutes such that about 8 wt. % of residue was left on a 90μm sieve. To 150 parts by weight of the thus-pulverized material, wereadded 4.5 parts by weight of sodium hydroxide as an alkaline activatorand 25 parts by weight of water, followed by mixing. The mixed mixturewas charged into a mold for forming a sample having a size of 2 cm×2cm×8 cm while vibration was applied to the mold.

The charged frame was placed in a thermostat-hygrostat chamber fromTabai which was set to a temperature of 50° C. Subsequently, thetemperature of the chamber was raised from 50° C. to 80° C. over about20 minutes at a relative humidity of 98%, and subsequently the chamberwas maintained at 80° C. for 4 hours (curing time), thereby obtaining asample.

Example 2-18

A mixture of 70 parts by weight of polymer-based sludge-incineratedashes of Example 2-11, 10 parts by weight of Ca(OH)₂ (first class gradechemical manufactured by Kanto Kagaku Co., Ltd.), and 20 parts by weightof crushed stone sludge described above in Example 13 was melted in anelectric furnace at a temperature of 1400° C. for 1 hour. The resultantmelt was poured into water to obtain vitric polymer-based sludge slag.This sludge slag was pulverized in 200 g portions in a disk mill for 10minutes such that about 8 wt. % of residue was left on a 90 μm sieve. To150 parts by weight of the thus-pulverized material, were added 4.5parts by weight of sodium hydroxide as an alkaline stimulator and 25parts by weight of water, followed by mixing. The mixed mixture wascharged into a mold for forming a sample having a size of 2 cm×2 cm×8 cmwhile vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber from Tabaiwhich was set to a temperature of 50° C. Subsequently, the temperatureof the chamber was raised from 50° C. to 80° C. over about 20 minutes ata relative humidity of 98%, and subsequently the chamber was maintainedat 80° C. for 4 hours (curing time), thereby obtaining a sample.

Example 2-19

A mixture of 40 parts by weight of polymer-based sludge-incineratedashes of Example 2-11, 40 parts by weight of Ca(OH)₂ (first class gradechemical manufactured by Kanto Kagaku Co., Ltd.), and 20 parts by weightof crushed stone sludge described above in Example 13 was melted in anelectric furnace at a temperature of 1500° C. for 1 hour. The resultantmelt was poured into water to obtain vitric polymer-based sludge slag.This sludge slag was pulverized in 200 g portions in a disk mill for 10minutes such that about 11 wt. % of residue was left on a 90 μm sieve.To 150 parts by weight of the thus-pulverized material, were added 2.3parts by weight of sodium hydroxide as an alkaline activator and 30parts by weight of water, followed by mixing. The mixed mixture wascharged into a mold for forming a sample having a size of 2 cm×2 cm×8 cmwhile vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber from Tabaiwhich was set to a temperature of 50° C. Subsequently, the temperatureof the chamber was raised from 50° C. to 80° C. over about 20 minutes ata relative humidity of 98%, and subsequently the chamber was maintainedat 80° C. for 4 hours (curing time), thereby obtaining a sample.

Example 2-20

A mixture of 50 parts by weight of polymer-based sludge-incineratedashes of Example 2-11 and 50 parts by weight of Ca(OH)₂ (first classgrade chemical manufactured by Kanto Kagaku Co., Ltd.) was melted in anelectric furnace at a temperature of 1550° C. for 1 hour. The resultantmelt was poured into water to obtain vitric polymer-based sludge slag.This sludge slag was pulverized in 200 g portions in a disk mill for 10minutes such that about 11 wt. % of residue was left on a 90 μm sieve.To 150 parts by weight of the thus-pulverized material, were added 4.5parts by weight of sodium hydroxide as an alkaline activator and 26parts by weight of water, followed by mixing. The mixed mixture showed aquick-setting property, but water was further added up to 33 parts byweight, followed by forced mixing. The resultant mixed mixture wascharged into a mold for forming a sample having a size of 2 cm×2 cm×8 cmwhile the mixture was rammed.

This formed object was placed in a thermostat-hygrostat chamber fromTabai which was set to a temperature of 50° C. Subsequently, thetemperature of the chamber was raised from 50° C. to 80° C. over about20 minutes at a relative humidity of 98%, and subsequently the chamberwas maintained at 80° C. for 4 hours (curing time), thereby obtaining asample.

Example 2-21

A mixture of 40 parts by weight of polymer-based sludge-incineratedashes of Example 2-11, 40 parts by weight of tricalcium phosphate (foodadditive manufactured by Wako Jyunyaku Kogyo Co., Ltd.), and 20 parts byweight of crushed stone sludge describe above in Example 13 was meltedin an electric furnace at a temperature of 1500° C. for 1 hour. Theresultant melt was poured into water to obtain vitric polymer-basedsludge slag. This sludge slag was pulverized in 200 g portions in a diskmill for 10 minutes such that about 10 wt. % of residue was left on a 90μm sieve. To 150 parts by weight of the thus-pulverized material, wereadded 4.5 parts by weight of sodium hydroxide as an alkaline activatorand 24 parts by weight of water, followed by mixing. The mixed mixturewas charged into a mold for forming a sample having a size of 2 cm×2cm×8 cm while vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber from Tabaiwhich was set to a temperature of 50° C. Subsequently, the temperatureof the chamber was raised from 50° C. to 80° C. over about 20 minutes ata relative humidity of 98%, and subsequently the chamber was maintainedat 80° C. for 4 hours (curing time), thereby obtaining a sample.

Example 2-22

Polymer-based sludge-incinerated ashes were melted in an electricfurnace at a temperature of 1400° C. for 1 hour. The resultant melt waspoured into water to obtain vitric polymer-based sludge slag (materialfrom Saitama Prefectural Sewerage Corp. having the following majorchemical composition (wt. %): SiO₂ 29.3, Al₂ O₃ 15.8, Fe₂ O₃ 13.0, CaO9.7, MgO 3.4, P₂ O₅ 22.5, S 0.05 Na₂ O 1.01, K₂ O 2.36, MnO 0.19, andothers). This sludge slag was pulverized in 200 g portions in a diskmill for 10 minutes such that about 8 wt. % of residue was left on a 90μm sieve. To 150 parts by weight of the thus-pulverized material, wereadded 4.5 parts by weight of sodium hydroxide as an alkaline activator,37.5 parts by weight of Ca(OH)₂, and 49 parts by weight of water,followed by mixing. The mixed mixture was charged into a mold forforming a sample having a size of 2 cm×2 cm×8 cm while vibration wasapplied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber from Tabaiwhich was set to a temperature of 50° C. Subsequently, the temperatureof the chamber was raised from 50° C. to 80° C. over about 20 minutes ata relative humidity of 98%, and subsequently the chamber was maintainedat 80° C. for 4 hours (curing time), thereby obtaining a sample.

Comparative Example 2-1

The pulverized material of lime-based sludge slag of Example 2-1 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 2-5 (however, an alkaline activator was notused) and through forming in a manner similar to that of Example 1,thereby obtaining a sample of 4-hour curing at 80° C.

This sample was different from a hardened product which was obtained inExample 1.

Comparative Example 2-2

100 parts by weight of sludge-incinerated ashes, which precedelime-based sludge slag of Example 2-1, was placed in each of a pluralityof beakers. Various mixtures of NaOH ranging in content from 1 to 5parts by weight and water ranging in content from 20 to 60 parts byweight were mixed. Through use of these materials, forming was performedin a manner similar to that of Example 2-1, followed by 4-hour curing at80° C.

The thus-prepared samples did not harden. The chemical composition ofincineration ashes is not much different from that of vitrified slagproduced from the incineration ashes, but hydraulicity or latenthydraulicity is not present. A conceivable reason for this is thatcompounds which constitute incineration ashes are in a stable form, andthus reaction does not further advance.

Tables 5 and 6 show measurements of compressive strength for samplesobtained in the above-described Examples 2-1 to 2-22.

                                      TABLE 5                                     __________________________________________________________________________                                        Formulation       Curing Conditions                                           (parts by weight) & Compressive           Composition of slag (wt. %)             Slag          strength                SiO.sub.2                                                                            CaO                                                                              Al.sub.2 O.sub.3                                                                   Fe.sub.2 O.sub.3                                                                  MgO R.sub.2 O                                                                        P.sub.2 O.sub.5                                                                   Cl                                                                              C/S powder                                                                            agg.                                                                              Stimul.                                                                            Water                                                                              (kgf/cm.sup.2)          __________________________________________________________________________    Ex.                                                                              32.1                                                                              34.4                                                                             14.1 4.5 2.4 1.31                                                                             8.0 --                                                                              1.15                                                                              Pulv.   NaOH      80° C. 2                                                               hours 98                2-1                                 1600     16  264  80° C. 4                                                               hours 153               Ex.                                                                              "                                Pulv.   NaOH      80° C. 1                                                               hour 404                2-2                                 1600     46  264  80° C. 2                                                               hours 524                                                                     80° C. 4                                                               hours 614                                                                     80° C. 22                                                              hours 787               Ex.                                                                              "                                Pulv.   NaOH      80° C. 1                                                               hour 449                2-3                                 1600     48  224  80° C. 2                                                               hours 526                                                                     80° C. 4                                                               hours 622               Ex.                                                                              "                                Pulv.   NaOH      20° C. 1 day                                                           46                      2-4                                 1600     48  264  20° C. 4                                                               days 205                Ex.                                                                              "                                Pulv.   NaOH      20° C. 1 day                                                           126                     2-5                                 1600     80  264  20° C. 3                                                               days 378                Ex.                                                                              "                                Pulv.   Ca(OH).sub.2                      2-6                                 1600     48  264  80° C. 4                                                               hours 54                                                    1600     160 288  80° C. 4                                                               hours 110                                                   1600     240 335  80° C. 4                                                               hours 108                                                   1600     320 352  80° C. 4                                                               hours 138                                                   1000    1000 880  80° C. 4                                                               hours 106               Ex.                                                                              "                                Pulv.                                                                             Agg.                                                                              NaOH                              2-7                                  713                                                                              1147                                                                               21.4                                                                              168  80° C. 4                                                               hours 306               Ex.                                                                              "                                Pulv.   NaOH                              2-8                                 1200      0  223  80° C. 4                                                               hours 211               Ex.                                                                              "                                Pulv.   NaOH                              2-9                                 1700     34  280.5                                                                              80° C. 4                                                               hours 407               Ex.                                                                              35.1                                                                              11.8                                                                             18.6 9.7 3.1 4.06                                                                             14.1                                                                              --                                                                              0.36                                                                              Pulv.   NaOH                              2-11                                 150      4.5                                                                              80   80° C. 4                                                               hours 21                Ex.                                                                              "                                Pulv.                                                                             NaOH                                                                              Ca(OH).sub.2                      2-12                                 150     37.5                                                                              45   80° C. 4                                                               hours 78                Ex.                                                                              "                                Pulv.                                                                             NaOH                                                                              Ca(OH).sub.2                      2-13                                 150                                                                                4.5                                                                              37.5                                                                              45   20° C. 1                                                               hour 14                 Ex.                                                                              "                                Pulv.                                                                             NaOH                                                                              Ca(OH).sub.2                      2-14                                 150                                                                                0.38                                                                             37.5                                                                              45   80° C. 4                                                               hours 72                Ex.                                                                              35.1                                                                              11.8                                                                             18.6 9.7 3.1 4.06                                                                             14.1                                                                              --                                                                              0.36                                                                              Pulv.                                                                             NaOH                                                                              Ca(OH).sub.2                      2-15                                 150                                                                                0.75                                                                             37.5                                                                              45   80° C. 4                                                               hours                   __________________________________________________________________________                                                          81                       Note) Agg.:Aggregate, Stimul.:Stimulator, Pulv.: Pulverized product      

                                      TABLE 6                                     __________________________________________________________________________    Ex.                                                                              26.4                                                                              32.9                                                                             15.1 7.0 2.5 2.84                                                                             10.4                                                                              0.0                                                                             1.34                                                                              Pulv.                                                                             NaOH                                  2-16                                150 4.5      27   80° C. 4                                                               hours 620               Ex.                                                                              31.2                                                                              25.7                                                                             15.3 7.8 2.9 3.41                                                                             10.5                                                                              0.0                                                                             0.88                                                                              Pulv.                                                                             NaOH                                  2-17                                150 4.5      24   80° C. 4                                                               hours 603               Ex.                                                                              36.1                                                                              18.1                                                                             17.6 8.5 3.2 3.75                                                                             10.0                                                                              0.0                                                                             0.54                                                                              Pulv.                                                                             NaOH                                  2-18                                150 4.5      25   80° C. 4                                                               hours 187               Ex.                                                                              27.9                                                                              38.8                                                                             15.9 5.3 2.2 2.17                                                                             6.2 0.0                                                                             1.49                                                                              Pulv.                                                                             NaOH                                  2-19                                150 1.5      30   80° C. 4                                                               hours 90                Ex.                                                                              20.4                                                                              46.7                                                                             14.6 4.7 1.8 1.72                                                                             7.9 0.0                                                                             2.45                                                                              Pulv.                                                                             NaOH                                  2-20                                150 4.5      33   80° C. 4                                                               hours 37                Ex.                                                                              24.9                                                                              28.7                                                                             11.3 5.4 2.3 2.54                                                                             22.9                                                                              0.0                                                                             1.23                                                                              Pulv.                                                                             NaOH                                  2-21                                150 4.5      24   80° C. 4                                                               hours 45                Ex.                                                                              29.3                                                                              9.7                                                                              15.8 13.0                                                                              3.4 3.37                                                                             22.5                                                                              --                                                                              0.35                                                                              Pulv.                                                                             NaOH                                                                              Ca(OH).sub.2                      2-22                                150 4.5 37.5 49   80° C. 4                                                               hours                   __________________________________________________________________________                                                          28.5                

As seen from Tables 5 and 6, a hardening composition of the presentinvention which contains fused slag produced from a sludge-incineratedsubstance and an alkaline activator becomes a hardened product havingexcellent strength merely by mixing with water and mixing and curing theresultant mixture.

Example 3-1

Municipal refuse-incinerated ashes from Asaka City, Saitama Prefecturewere melted in an electric furnace at a temperature of 1400° C. for 1hour. The resultant melt was poured into water to obtain refuse slag(major chemical composition (wt. %): SiO₂ 30.1, Al₂ O₃ 20.5, Fe₂ O₃ 8.2,CaO 28.0, MgO 4.5, P₂ O₅ 1.85, SO₃ 0.1, Na₂ O 1.36, K₂ O 0.24, Cl 1.08,and others). This refuse slag was pulverized in 200 g portions in a diskmill for 10 minutes such that fineness becomes about a Blaine value of2100 cm² /g. To 400 parts by weight of the thus-pulverized material,were added 12 parts by weight of sodium hydroxide as an alkalineactivator and 68 parts by weight of water, followed by mixing in aHobart mixer. The mixed mixture was charged into a mold for forming asample having a size of 2 cm×2 cm×8 cm while vibration was applied tothe mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 4 hours (and 8 hours) (curingtime), thereby obtaining a sample.

Example 3-2

A mixture of 60 parts by weight of municipal refuse-incinerated ashes ofExample 3-1, 20 parts by weight of crushed stone sludge (material fromYukou Kogyo Co., Ltd. having the following major chemical composition(wt. %): SiO₂ 54.4, Al₂ O₃ 18.6, Fe₂ O₃ 6.2, CaO 5.6, MgO 2.8, Na₂ O3.08, K₂ O 1.67, and others), and 20 parts by weight of tricalciumphosphate (food additive manufactured by Wako Jyunyaku Kogyo Co., Ltd.)was melted in an electric furnace at a temperature of 1400° C. for 1hour. The resultant melt was poured into water to obtain vitric refuseslag. This refuse slag was used to prepare a sample through mixing andcuring under conditions similar to those of Example 3-1, therebyobtaining a sample of 4-hour curing at 80° C. and a sample of 8-hourcuring at 80° C. Table 7 shows the chemical composition of this slag.

Example 3-3

Municipal refuse-incinerated ashes from Yokohama City were melted in anelectric furnace at a temperature of 1400° C. for 1 hour. The resultantmelt was poured into water to obtain refuse slag (major chemicalcomposition (wt. %): SiO₂ 39.2, Al₂ O₃ 16.0, Fe₂ O₃ 11.8, CaO 20.0, MgO3.4, P₂ O₅ 1.9, SO₃ 0.5, Na₂ O 2.75, K₂ O 1.38, Cl 0.4, and others).This refuse slag was pulverized in 200 g portions in a disk mill for 10minutes such that fineness becomes about a Blaine value of 2100 cm² /g.To 600 parts by weight of the thus-pulverized material, were added 9parts by weight of sodium hydroxide as an alkaline activator and 111parts by weight of water, followed by mixing in a Hobart mixer. Themixed mixture was charged into a mold for forming a sample having a sizeof 2 cm×2 cm×8 cm while vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 4 hours, 8 hours, and 16 hours(curing time), thereby obtaining respective samples.

Example 3-4

The pulverized slag material of Example 3-3 was used to prepare a samplethrough mixing and curing under conditions similar to those of Example3-3 except that the amount of NaOH was 18 parts by weight, therebyobtaining samples of 2-hour, 4-hour, and 22-hour curing at 80° C.

Table 7 shows measurements of compressive strength for samples obtainedin the above-described Examples 3-1 to 3-4.

                                      TABLE 7                                     __________________________________________________________________________                                        Formulation      Curing Conditions                                            (parts by weight)                                                                              & Compressive            Composition of slag (wt. %)             Slag         strength                 SiO.sub.2                                                                            CaO                                                                              Al.sub.2 O.sub.3                                                                   Fe.sub.2 O.sub.3                                                                  MgO R.sub.2 O                                                                        P.sub.2 O.sub.5                                                                   Cl                                                                              C/S powder                                                                            agg.                                                                              Stimul.                                                                            Water                                                                             (kgf/cm.sup.2)           __________________________________________________________________________    Ex.                                                                              30.1                                                                              28.0                                                                             20.5 8.2 4.5 1.60                                                                             1.85                                                                              1.1                                                                             1.00                                                                              Pulv.   NaOH     80° C. 4                                                               hours 511                3-1                                 400     12   68  80° C. 8                                                               hours 612                Ex.                                                                              27.6                                                                              28.9                                                                             16.3 6.2 3.5 2.57                                                                             10.5                                                                              1.7                                                                             1.12                                                                              Pulv.   NaOH     80° C. 1 hour                                                          404                      3-2                                 400     12   68  80° C. 2                                                               hours 524                                                                        4 hours 614                                                                80 ° C. 22                                                             hours 787                Ex.                                                                              39.2                                                                              20.0                                                                             16.0 11.8                                                                              3.4 4.15                                                                             1.9 0.4                                                                             0.55                                                                              Pulv.   NaOH     80° C. 4                                                               hours 322                3-3                                 600      9   111 80° C. 8                                                               hours 459                                                                        16 hours 519          Ex.                                                                              "                                Pulv.   NaOH     80° C. 4                                                               hours 841                3-4                                 600     18   111 80° C. 8                                                               hours 997                                                                        16 hours              __________________________________________________________________________                                                         1128                 

As seen from Table 8, a hardening composition of the present inventionwhich contains fused slag produced from a refuse-incinerated substanceand an alkaline activator becomes a hardened product having excellentstrength merely by mixing with water and curing the resultant mixture.

Example 4-1

Municipal refuse-incinerated ashes from Yokohama City contained in analumina container were melted in an electric furnace at a temperature of1400° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 39.1, Al₂ O₃ 15.6,Fe₂ O₃ 12.3, CaO 20.3, MgO 3.3, SO₃ 0.6, Na₂ O 2.70, K₂ O 1.41, TiO₂1.74, P₂ O₅ 1.70, and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 17.6 wt. % ofresidue was left on a 90 μm sieve and about 31 wt. % of residue was lefton a 63 μm sieve. To 600 parts by weight of the thus-pulverizedmaterial, were added 180 parts by weight of a commercially availablealkali silicate solution (water glass No. 1) and 30 parts by weight ofwater, followed by mixing in a Hobart mixer. The mixed mixture wascharged into a mold for forming a sample having a size of 2 cm×2 cm×8 cmwhile vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 4 hours (8 hours and 16 hours)(curing time), thereby obtaining a sample.

Example 4-2

The pulverized material of refuse slag of Example 4-1 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of water glass No.3 as alkali silicate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-3

The pulverized material of refuse slag of Example 4-1 and water glassNo. 1 as alkali silicate were used to prepare a sample through mixingand forming under conditions similar to those of Example 4-1. The formedmaterial was cured in a humid environment at a temperature of 20° C. for3 days (and 7 days).

Example 4-4

200 parts by weight of the pulverized material of refuse slag of Example4-1, 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the refuse slag, 120 parts by weightof water glass No. 1, and 10 parts by weight of water were mixed andsubsequently processed in a manner similar to that of Example 4-1,thereby obtaining a sample.

Example 4-5

200 parts by weight of the pulverized material of refuse slag of Example4-1, 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the refuse slag, and 120 parts byweight of water glass No. 3 were mixed and subsequently processed in amanner similar to that of Example 4-1, thereby obtaining a sample.

Example 4-6

200 parts by weight of the pulverized material of refuse slag of Example4-1, 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the refuse slag, and 120 parts byweight of soda aluminate (product #2019 manufactured by Asada KagakuKogyo, Co., Ltd.) were mixed and subsequently processed in a mannersimilar to that of Example 4-1, thereby obtaining a sample.

Example 4-7

200 parts by weight of the pulverized material of refuse slag of Example4-1, 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the refuse slag, and 120 parts byweight of soda aluminate (product #1219 manufactured by Asada KagakuKogyo, Co., Ltd.) were mixed and subsequently processed in a mannersimilar to that of Example 4-1, thereby obtaining a sample.

Example 4-8

A mixture of 90 parts by weight of municipal refuse- incinerated ashesfrom Yokohama City and 10 parts by weight of calcium hydroxide (specialgrade chemical manufactured by Kanto Kagaku Co., Ltd.) contained in analumina container was melted in an electric furnace at a temperature of1400° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 35.1, Al₂ O₃ 14.4,Fe₂ O₃ 11.9, CaO 27.2, MgO 2.9, SO₃ 0.7, Na₂ O 2.29, K₂ O 1.10, TiO₂1.5, P₂ 0₅ 1.5, and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 14.4 wt. % ofresidue was left on a 90 μm sieve and about 27.9 wt. % of residue wasleft on a 63 μm sieve. To 600 parts by weight of the thus-pulverizedmaterial, were added 180 parts by weight of water glass No. 1 and 30parts by weight of water, followed by mixing in a Hobart mixer. Theresulting mixed mixture was processed in a manner similar to that ofExample 4-1, thereby obtaining a sample.

Example 4-9

The pulverized material of refuse slag of Example 4-8 a and water glassNo. 1 as alkali silicate were used to prepare a sample through mixingand forming under conditions similar to those of Example 4-1. The formedmaterial was cured in a humid environment at a temperature of 20° C. for3 days (7 days and 28 days).

Example 4-10

The pulverized material of refuse slag of Example 4-8 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of water glass No.3 as alkali silicate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-11

A mixture of 80 parts by weight of municipal refuse-incinerated ashesfrom Yokohama City and 20 parts by weight of calcium hydroxide (specialgrade chemical manufactured by Kanto Kagaku Co., Ltd.) contained in analumina container was melted in an electric furnace at a temperature of1400° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 31.5, Al₂ O₃ 13.3,Fe₂ O₃ 10.3, CaO 34.4, MgO 2.7, SO₃ 0.9, Na₂ O 2.08, K₂ O 0.89, TiO₂1.4, P₂ O₅ 1.4, and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 16.1 wt. % ofresidue was left on a 90 μm sieve and about 26.1 wt. % of residue wasleft on a 63 μm sieve. To 600 parts by weight of the thus-pulverizedmaterial, were added 180 parts by weight of water glass No. 1 and 30parts by weight of water, followed by mixing in a Hobart mixer. Theresulting mixed mixture was processed in a manner similar to that ofExample 4-1, thereby obtaining a sample.

Example 4-12

The pulverized material of refuse slag of Example 4-11 and water glassNo. 1 as alkali silicate were used to prepare a sample through mixingand forming under conditions similar to those of Example 4-1. The formedmaterial was cured in a humid environment at a temperature of 20° C. for3 days (7 days and 28 days).

Example 4-13

The pulverized material of refuse slag of Example 4-11 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of water glass No.3 as alkali silicate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-14

A mixture of 70 parts by weight of municipal refuse-incinerated ashesfrom Yokohama City and 30 parts by weight of calcium hydroxide (specialgrade chemical manufactured by Kanto Kagaku Co., Ltd.) contained in analumina container was melted in an electric furnace at a temperature of1500° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 27.4, Al₂ O₃ 18.1,Fe₂ O₃ 8.1, CaO 39.0, MgO 2.1, SO₃ 0.1, Na₂ O 1.63, K₂ O 0.51, TiO₂ 0.9,P₂ O₅ 1.2, and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 17.8 wt. % ofresidue was left on a 90 μm sieve and about 31.3 wt. % of residue wasleft on a 63 μm sieve. To 600 parts by weight of the thus-pulverizedmaterial, were added 180 parts by weight of water glass No. 3, followedby mixing in a Hobart mixer. The resulting mixed mixture was processedin a manner similar to that of Example 4-1, thereby obtaining a sample.Example 4-15

A mixture of 60 parts by weight of municipal refuse-incinerated ashesfrom Yokohama City and 40 parts by weight of calcium hydroxide (specialgrade chemical manufactured by Kanto Kagaku Co., Ltd.) contained in analumina container was melted in an electric furnace at a temperature of1550° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 21.9, Al₂ O₃ 24.0,Fe₂ O₃ 6.7, CaO 40.7, MgO 1.8, SO₃ 0.4, Na₂ O 1.41, K₂ O 0.42, TiO₂ 0.9,P₂ O₅ 0.9, and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 19 wt. % ofresidue was left on a 90 μm sieve and about 31.1 wt. % of residue wasleft on a 63 μm sieve. To 600 parts by weight of the thus-pulverizedmaterial, were added 180 parts by weight of water glass No. 1 and 30parts by weight of water, followed by mixing in a Hobart mixer. However,the mixture set during mixing, indicating the quick-hardening property.Thus, no sample for strength test was prepared from this mixture. AnX-ray analysis revealed that this refuse slag was not completelyvitrified.

Example 4-16

A mixture of 40 parts by weight of municipal refuse-incinerated ashesfrom Yokohama City and 60 parts by weight of crushed stone sludge (wastematerial supplied by Yukou Kogyo Co., Ltd.) contained in an aluminacontainer was melted in an electric furnace at a temperature of 1400° C.for 1 hour. The resultant melt was poured into water to obtain refuseslag (major chemical composition (wt. %): SiO₂ 54.3, Al₂ O₃ 17.9, Fe₂ O₃6.8, CaO 7.7, MgO 3.5, SO₃ 0.3, Na₂ O 3.55, K₂ O 1.18, TiO₂ 1.0, P₂ O₅0.4, Cl 0.0, and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 11 wt. % ofresidue was left on a 90 μm sieve and about 25.5 wt. % of residue wasleft on a 63 μm sieve. To 600 parts by weight of the thus-pulverizedmaterial, were added 180 parts by weight of water glass No. 1 and 30parts by weight of water, followed by mixing in a Hobart mixer. Theresulting mixed mixture was processed in a manner similar to that ofExample 4-1, thereby obtaining a sample.

Example 4-17

The pulverized material of refuse slag of Example 4-16 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of water glass No.3 as alkali silicate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-18

The pulverized material of refuse slag of Example 4-16 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of a soda aluminatesolution (product #2019 manufactured by Asada Kagaku, Co., Ltd.) asalkali aluminate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-19

Municipal refuse-incinerated ashes from Kumagaya City contained in analumina container were melted in an electric furnace at a temperature of1400° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 36.6, Al₂ O₃ 17.7,Fe₂ O₃ 5.9, CaO 23.4, MgO 3.8, SO₃ 0.2, Na₂ O 3.42, K₂ O 1.82, TiO₂ 1.9,P₂ O₅ 3.5, MnO 0.1 and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 18.1 wt. % ofresidue was left on a 90 μm sieve and about 31 wt. % of residue was lefton a 63 μm sieve. To 200 parts by weight of the thus-pulverized materialand 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the refuse slag, were added 20 partsby weight of a commercially available alkali silicate solution (waterglass No. 1) and 36 parts by weight of water, followed by mixing in aHobart mixer. The mixed mixture was charged into a mold for forming asample having a size of 2 cm×2 cm×8 cm while vibration was applied tothe mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 4 hours (8 hours and 16 hours)(curing time), thereby obtaining a sample.

Example 4-20

200 parts by weight of the pulverized material of refuse slag of Example4-19, 200 parts by weight of aggregate having a grain size of 0.5 to2.38 mm prepared by coarsely pulverizing the refuse slag, 40 parts byweight of water glass No. 1, and 32 parts by weight of water were mixedand subsequently processed in a manner similar to that of Example 4-1,thereby obtaining a sample.

Example 4-21

200 parts by weight of the pulverized material of refuse slag of Example4-19, 200 parts by weight of aggregate having a grain size of 0.5 to2.38 mm prepared by coarsely pulverizing the refuse slag, 80 parts byweight of water glass No. 1, and 16 parts by weight of water were mixedand subsequently processed in a manner similar to that of Example 4-1,thereby obtaining a sample.

Example 4-22

200 parts by weight of the pulverized material of refuse slag of Example4-19, 200 parts by weight of aggregate having a grain size of 0.5 to2.38 mm prepared by coarsely pulverizing the refuse slag, 120 parts byweight of water glass No. 1, and 8 parts by weight of water were mixedand subsequently processed in a manner similar to that of Example 4-1,thereby obtaining a sample.

Example 4-23

200 parts by weight of the pulverized material of refuse slag of Example4-19, 200 parts by weight of aggregate having a grain size of 0.5 to2.38 mm prepared by coarsely pulverizing the refuse slag, and 200 partsby weight of water glass No. 1 were mixed and subsequently processed ina manner similar to that of Example 4-1, thereby obtaining a sample.

Example 4-24

200 parts by weight of the pulverized material of refuse slag of Example4-19, 200 parts by weight of aggregate having a grain size of 0.5 to2.38 mm prepared by coarsely pulverizing the refuse slag, and 400 partsby weight of water glass No. 1 were mixed and subsequently processed ina manner similar to that of Example 4-1, thereby obtaining a sample.

Example 4-25

200 parts by weight of the pulverized material of refuse slag of Example4-19, 200 parts by weight of aggregate having a grain size of 0.5 to2.38 mm prepared by coarsely pulverizing the refuse slag, and 80 partsby weight of water glass No. 3 were mixed and subsequently processed ina manner similar to that of Example 4-1, thereby obtaining a sample.

Example 4-26

200 parts by weight of the pulverized material of refuse slag of Example4-19, 200 parts by weight of aggregate having a grain size of 0.5 to2.38 mm prepared by coarsely pulverizing the refuse slag, and 80 partsby weight of a soda aluminate solution (product #2019 manufactured byAsada Kagaku, Co., Ltd.) as alkali aluminate were mixed and subsequentlyprocessed in a manner similar to that of Example 4-1, thereby obtaininga sample.

Example 4-27

Municipal refuse-incinerated ashes (principal ashes) from Kumagaya Citycontained in an alumina container were melted in an electric furnace ata temperature of 1400° C. for 1 hour. The resultant melt was poured intowater to obtain refuse slag (major chemical composition (wt. %): SiO₂30.6, Al₂ O₃ 19.1, Fe₂ O₃ 2.0, CaO 30.9, MgO 5.6, SO₃ 2.1, Na₂ O 1.50,K₂ O 0.51, TiO₂ 3.1, P₂ O₅ 2.2, MnO 0.1 and others). This refuse slagwas pulverized in 200 g portions in a disk mill for 10 minutes such thatabout 15.1 wt. % of residue was left on a 90 μm sieve and about 25.5 wt.% of residue was left on a 63 μm sieve. To 600 parts by weight of thethus-pulverized material, were added 180 parts by weight of acommercially available alkali silicate solution (water glass No. 1) and30 parts by weight of water, followed by mixing in a Hobart mixer. Themixed mixture was charged into a mold for forming a sample having a sizeof 2 cm×2 cm×8 cm while vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 4 hours (8 hours and 16 hours)(curing time), thereby obtaining a sample.

Example 4-28

The pulverized material of refuse slag of Example 4-27 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of water glass No.3 as alkali silicate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-29

The pulverized material of refuse slag of Example 4-27 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of a soda aluminatesolution (product #2019 manufactured by Asada Kagaku, Co., Ltd.) asalkali aluminate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-30

A mixture of 100 parts by weight of municipal refuse-incinerated ashes(principal ashes) from Kumagaya City and 50 parts by weight of municipalrefuse-incinerated ashes (fly ashes) from Kumagaya City contained in analumina container was melted in an electric furnace at a temperature of1400° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 34.1, Al₂ O₃ 17.5,Fe₂ O₃ 5.0, CaO 26.3, MgO 4.1, SO₃ 1.4, Na₂ O 2.71, K₂ O 1.20, TiO₂ 2.2,P₂ O₅ 3.1, MnO 0.1 and others). This refuse slag was pulverized in 200 gportions in a disk mill for 10 minutes such that about 15.6 wt. % ofresidue was left on a 90 μm sieve and about 26.3 wt. % of residue wasleft on a 63 μm sieve. To 200 parts by weight of the thus-pulverizedmaterial and 200 parts by weight of aggregate having a grain size of 0.5to 2.38 mm prepared by coarsely pulverizing the refuse slag, were added90 parts by weight of a commercially available alkali silicate solution(water glass No. 1) and 10 parts by weight of water. The resultingmixture was processed through mixing and curing under conditions similarto those of Example 4-1, thereby obtaining samples of 4-hour, 8-hour,and 16-hour curing at 80° C.

Example 4-31

The pulverized material of refuse slag of Example 4-30 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 90 parts by weight of a commerciallyavailable alkali silicate solution (water glass No. 1), 10 parts byweight of water, and 90 parts by weight of water glass No. 3 as alkalisilicate were added to 200 parts by weight of the pulverized materialand 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the refuse slag, thereby obtainingsamples of 4-hour, 8-hour, and 16-hour curing at 80° C.

Example 4-32

The pulverized material of refuse slag of Example 4-30 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 90 parts by weight of soda aluminate(product #2019 manufactured by Asada Kagaku, Co., Ltd.) as alkalialuminate was added to 200 parts by weight of the pulverized materialand 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the refuse slag, thereby obtainingsamples of 4-hour, 8-hour, and 16-hour curing at 80° C.

Example 4-33

Fines were removed from municipal refuse-incinerated ashes (principalashes) from Kumagaya City using a 2.38 mm sieve. The residual material,which is conceivably rich in glass refuse and metallic refuse such asaluminum cans, contained in an alumina container was melted in anelectric furnace at a temperature of 1400° C. for 1 hour. The resultantmelt was poured into water to obtain refuse slag (major chemicalcomposition (wt. %): SiO₂ 54.6, Al₂ O₃ 9.7, Fe₂ O₃ 3.1, CaO 17.6, MgO2.0, SO₃ 0.1, Na₂ O 7.49, K₂ O 1.38, TiO₂ 1.1, P₂ O₅ 1.7, MnO 0.1, Cl0.1 and others). This refuse slag was pulverized in 200 g portions in adisk mill for 10 minutes such that about 26 wt. % of residue was left ona 90 μm sieve and about 35.6 wt. % of residue was left on a 63 μm sieve.To 600 parts by weight of the thus-pulverized material, were added 180parts by weight of water glass No. 1 and 30 parts by weight of water,followed by mixing in a Hobart mixer. The mixed mixture was subsequentlyprocessed in a manner similar to that of Example 4-1, thereby obtainingsamples.

The thus-obtained samples all swelled after curing. Therefore, theirsurface portions were cut off using a diamond cutter to obtain samples,each having a size of 2 cm×2 cm×8 cm, for strength measurement use.

This swell during curing is conceivably caused in the followingmechanism. Since a metal reactive to alkali, particularly aluminumremains in the form of metal in refuse slag and sludge slag, such ametal reacts with alkaline water glass to produce a hydrogen gas, whoseexpansion pressure causes the samples to swell. This indicates that alight-weight hardened product similar to ALC (autoclaved light-weightconcrete) can be readily obtained with no requirement ofhigh-temperature high-pressure curing in an autoclave.

Example 4-34

The pulverized material of refuse slag of Example 4-33 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of water glass No.3 as alkali silicate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

These samples all swelled after curing. Therefore, their surfaceportions were cut off using a diamond cutter to obtain samples, eachhaving a size of 2 cm×2 cm×8 cm, for strength measurement use.

Example 4-35

The pulverized material of refuse slag of Example 4-33 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of a soda aluminatesolution (product #2019 manufactured by Asada Kagaku, Co., Ltd.) asalkali aluminate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

These samples all swelled after curing. Therefore, their surfaceportions were cut off using a diamond cutter to obtain samples, eachhaving a size of 2 cm×2 cm×8 cm, for strength measurement use.

Example 4-36

A mixture of 10 parts by weight of municipal refuse-incinerated ashes(principal ashes) from Kumagaya City and 90 parts by weight of crushedstone sludge (waste material supplied by Yukou Kogyo Co., Ltd.)contained in an alumina container was melted in an electric furnace at atemperature of 1400° C. for 1 hour. The resultant melt was poured intowater to obtain refuse slag (major chemical composition (wt. %): SiO₂54.6, Al₂ O₃ 18.1, Fe₂ O₃ 6.7, CaO 7.7, MgO 3.5, SO₃ 0.3, Na₂ O 3.55, K₂O 1.18, TiO₂ 1.0, P₂ O₅ 0.4, MnO 0.1, Cl 0.0, and others). This refuseslag was pulverized in 200 g portions in a disk mill for 10 minutes suchthat about 28 wt. % of residue was left on a 90 μm sieve and about 28wt. % of residue was left on a 63 μm sieve. To 600 parts by weight ofthe thus-pulverized material, were added 180 parts by weight of waterglass No. 1 and 30 parts by weight of water, followed by mixing in aHobart mixer. The resulting mixed mixture was processed in a mannersimilar to that of Example 4-1, thereby obtaining a sample. Example 4-37

The pulverized material of refuse slag of Example 4-36 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of water glass No.3 as alkali silicate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-38

The pulverized material of refuse slag of Example 4-36 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-1 except that 180 parts by weight of a soda aluminatesolution (product #2019 manufactured by Asada Kagaku, Co., Ltd.) asalkali aluminate was added to 600 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

Example 4-39

Refuse slag (major chemical composition (wt. %): SiO₂ 36.6, Al₂ O₃ 18.8,Fe₂ O₃ 8.2, CaO 21.5, MgO 3.7, SO₃ 0.3, Na₂ O 3.24, K₂ O 1.33, TiO₂ 2.2,P₂ O₅ 2.5, MnO 0.2, Cl 0.3 and others) obtained from municipal refusefrom Eastern Association of Public Cleaning, Yoshikawa-cho, Saitama, waspulverized in 200 g portions in a disk mill for 10 minutes such thatabout 12.8 wt. % of residue was left on a 90 μm sieve and about 26 wt. %of residue was left on a 63 μm sieve. To 1800 parts by weight of thethus-pulverized material, were added 540 parts by weight of acommercially available alkali silicate solution (water glass No. 1) and90 parts by weight of water, followed by mixing in a Hobart mixer. Themixed mixture was charged into a mold for forming a sample having a sizeof 4 cm×4 cm×16 cm while vibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 4 hours (8 hours and 16 hours)(curing time), thereby obtaining a sample.

These samples all swelled after curing. Therefore, their surfaceportions were cut off using a diamond cutter to obtain samples forstrength measurement use.

Example 4-40

The pulverized material of refuse slag of Example 4-39 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-37 except that 540 parts by weight of water glass No.3 as alkali silicate was added to 1800 parts by weight of the pulverizedmaterial, thereby obtaining samples of 4-hour, 8-hour, and 16-hourcuring at 80° C.

As in Example 4-33, these samples all swelled after curing. Therefore,their surface portions were cut off using a diamond cutter to obtainsamples, each having a size of 4 cm×4 cm×16 cm, for strength measurementuse.

Example 4-41

The pulverized material of refuse slag of Example 4-39 was used toprepare a sample through mixing and curing under conditions similar tothose of Example 4-37 except that 540 parts by weight of a sodaaluminate solution (product #2019 manufactured by Asada Kagaku, Co.,Ltd.) as alkali aluminate was added to 600 parts by weight of thepulverized material, thereby obtaining samples of 4-hour, 8-hour, and16-hour curing at 80° C.

As in Example 4-33, these samples all swelled after curing. Therefore,their surface portions were cut off using a diamond cutter to obtainsamples, each having a size of 4 cm×4 cm×16 cm, for strength measurementuse.

As described above, swelling occurred during curing for samples ofExamples 4-33 to 4-35 and Examples 4-39 to 4-41. This swell duringcuring is conceivably caused in the following mechanism. Since a metalreactive to alkali, particularly aluminum remains in the form of metalin refuse slag, such a metal reacts with alkaline water glass or sodaaluminate to produce a hydrogen gas, whose expansion pressure causes thesamples to swell. This indicates that a light-weight hardened productsimilar to ALC (autoclaved light-weight concrete) can be readilyobtained with no requirement of high-temperature high-pressure curing inan autoclave. Further, an example is not given herein, but when refuseslag is obtained from classified refuse which does not contain metallicaluminum, it is confirmed that a similar ALC-like hardened body can beobtained from such refuse slag or sludge slag through addition ofmetallic aluminum powder thereto. This can be one of features of thepresent invention.

Example 4-42

A mixture of 160 parts by weight of municipal refuse-incinerated ashesfrom Yokohama City and 5 parts by weight of sodium fluoride (specialgrade chemical manufactured by Kanto Kagaku Co., Ltd.) contained in analumina container was melted in an electric furnace at a temperature of1300° C. for 1 hour. The resultant melt was poured into water to obtainrefuse slag (major chemical composition (wt. %): SiO₂ 37.1, Al₂ O₃ 14.9,Fe₂ O₃ 11.6, CaO 19.3, MgO 3.1, SO₃ 0.6, Na₂ O 6.04, K₂ O 1.30, TiO₂1.5, P₂ O₅ 1.5, F 2.1 and others). This refuse slag was pulverized in200 g portions in a disk mill for 10 minutes such that about 23.5 wt. %of residue was left on a 90 μm sieve and about 35.6 wt. % of residue wasleft on a 63 μm sieve. To 600 parts by weight of the thus-pulverizedmaterial, were added 180 parts by weight of water glass No. 3, followedby mixing in a Hobart mixer. The mixed mixture was subsequentlyprocessed in a manner similar to that of Example 4-1, thereby obtaininga sample.

Example 4-43

A mixture of 80 parts by weight of municipal refuse-incinerated ashesfrom Yokohama City and 20 parts by weight of calcium hydrogenphosphate2-hydrate (special grade chemical manufactured by Kanto Kagaku Co.,Ltd.) contained in an alumina container was melted in an electricfurnace at a temperature of 1300° C. for 1 hour. The resultant melt waspoured into water to obtain refuse slag (major chemical composition (wt.%): SiO₂ 31.0, Al₂ O₃ 12.6, Fe₂ O₃ 9.7, CaO 26.5, MgO 2.6, SO₃ 0.5, Na₂O 2.11, K₂ O 1.12, TiO₂ 1.3, P₂ O₅ 9.6, and others). This refuse slagwas pulverized in 200 g portions in a disk mill for 10 minutes such thatabout 13.6 wt. % of residue was left on a 90 μm sieve and about 26.3 wt.% of residue was left on a 63 μm sieve. To 600 parts by weight of thethus-pulverized material, were added 180 parts by weight of water glassNo. 1 and 30 parts by weight of water, followed by mixing in a Hobartmixer. The mixed mixture was subsequently processed in a manner similarto that of Example 4-1, thereby obtaining a sample.

Example 4-44

Lime-based sludge slag (material from Osaka Municipal Sewerage Corp.having the following major chemical composition (wt. %): SiO₂ 33.4, Al₂O₃ 14.2, Fe₂ O₃ 5.0, CaO 33.9, MgO 2.4, P₂ O₅ 7.0, S 1.1, Na₂ O 0.75, K₂O 0.68, and others) was pulverized in 200 g portions in a disk mill for10 minutes such that about 10 wt. % of residue was left on a 90 μm sieveand about 26 wt. % of residue was left on a 63 μm sieve. To 900 parts byweight of the thus-pulverized material, were added 270 parts by weightof water glass No. 1 and 45 parts by weight of water. The resultantmixture was mixed in a Hobart mixer. The mixed mixture was charged intoa mold for forming a sample having a size of 2 cm×2 cm×8 cm to be usedin a strength test of normal portland cement mortar, while vibration wasapplied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over about 3 hours at a relative humidity of 98%, andsubsequently the chamber was maintained at 80° C. for 4 hours (8 hoursand 16 hours) (curing time), thereby obtaining a sample.

Some 8-hour-cured samples were immersed in 10% hydrochloric acid andsulfuric acid solutions for 7 and 14 days, respectively, to therebyprepare acid-resistance-tested samples.

Example 4-45

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 4-1 except that 270 parts by weight of waterglass No. 3 was added to 900 parts by weight of the pulverized material,thereby obtaining samples of 4-hour, 8-hour, and 16-hour curing at 80°C. Some 8-hour-cured samples were immersed in 10% hydrochloric acid andsulfuric acid solutions for 7 and 14 days, respectively, to therebyprepare acid-resistance-tested samples.

Example 4-46

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 4-1 except that 20 parts by weight of waterglass No. 1 and 32 parts by weight of water were added to 150 parts byweight of the pulverized material and 200 parts by weight of aggregatehaving a grain size of 0.5 to 2.38 mm prepared by coarsely pulverizingthe sludge slag, thereby obtaining samples of 4-hour, 8-hour, and16-hour curing at 80° C.

Example 4-47

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 4-1 except that 40 parts by weight of waterglass No. 1 and 24 parts by weight of water were added to 150 parts byweight of the pulverized material and 200 parts by weight of aggregatehaving a grain size of 0.5 to 2.38 mm prepared by coarsely pulverizingthe sludge slag, thereby obtaining samples of 4-hour, 8-hour, and16-hour curing at 80° C.

Example 4-48

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 4-1 except that 80 parts by weight of waterglass No. 1 and 16 parts by weight of water were added to 150 parts byweight of the pulverized material and 200 parts by weight of aggregatehaving a grain size of 0.5 to 2.38 mm prepared by coarsely pulverizingthe sludge slag, thereby obtaining samples of 4-hour, 8-hour, and16-hour curing at 80° C.

Example 4-49

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 4-1 except that 180 parts by weight of waterglass No. 1 and 7.5 parts by weight of water were added to 300 parts byweight of the pulverized material and 300 parts by weight of aggregatehaving a grain size of 0.5 to 2.38 mm prepared by coarsely pulverizingthe sludge slag, thereby obtaining samples of 4-hour, 8-hour, and16-hour curing at 80° C.

Example 4-50

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 4-1 except that 200 parts by weight of waterglass No. 1 was added to 200 parts by weight of the pulverized materialand 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the sludge slag, thereby obtainingsamples of 4-hour, 8-hour, and 16-hour curing at 80° C.

Example 4-51

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 3-1 except that 400 parts by weight of waterglass No. 1 was added to 200 parts by weight of the pulverized materialand 200 parts by weight of aggregate having a grain size of 0.5 to 2.38mm prepared by coarsely pulverizing the sludge slag, thereby obtainingsamples of 4-hour, 8-hour, and 16-hour curing at 80° C.

Example 4-52

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a mixture in a manner similar to that of Example 4-1except that 450 parts by weight of water glass No. 1 and 40 parts byweight of water were added to 900 parts by weight of the pulverizedmaterial and 900 parts by weight of aggregate having a grain size of 0.5to 2.38 mm prepared by coarsely pulverizing the sludge slag. Theresulting mixture was mixed under conditions similar to those of Example4-1. The mixed mixture was charged into a mold for forming a samplehaving a size of 4 cm×4 cm×8 cm while vibration was applied to the mold,followed by curing in a humid environment at 20° C. to thereby obtainsamples of 3-day, 7-day, and 28-day curing.

Example 4-53

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a mixture in a manner similar to that of Example 4-1except that 450 parts by weight of water glass No. 1 and 40 parts byweight of water were added to 900 parts by weight of the pulverizedmaterial and 900 parts by weight of aggregate having a grain size of 0.5to 2.38 mm prepared by coarsely pulverizing the sludge slag. Theresulting mixture was mixed under conditions similar to those of Example4-1. The mixed mixture was charged into a mold for forming a samplehaving a size of 4 cm×4 cm×8 cm while vibration was applied to the mold.The thus-formed material was cured for 3 days in a humid environment at20° C., and subsequently cured under water at 20° C., thereby obtainingsamples of 14-day and 28-day curing after formation.

Example 4-54

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a mixture in a manner similar to that of Example 4-1except that 297 parts by weight of water glass No. 1 and 60 parts byweight of water were added to 630 parts by weight of the pulverizedmaterial and 1170 parts by weight of aggregate having a grain size of0.5 to 2.38 mm prepared by coarsely pulverizing the sludge slag. Theresulting mixture was mixed under conditions similar to those of Example4-1. The mixed mixture was charged into a mold for forming a samplehaving a size of 4 cm×4 cm×8 cm while vibration was applied to the mold,followed by curing in a humid environment at 20° C. to thereby obtainsamples of 3-day, 7-day, and 28-day curing.

Example 4-55

Polymer-based sludge-incinerated ashes were melted in an electricfurnace at a temperature of 1400° C. for 1 hour. The resultant melt waspoured into water to obtain vitric polymer-based sludge slag (materialfrom Saitama Prefectural Sewerage Corp. having the following majorchemical composition (wt. %): SiO₂ 29.6, Al₂ O₃ 16.6, Fe₂ O₃ 13.4, CaO10.0, MgO 3.5, P₂ O₅ 20.5, SO₂ 0.0, Na₂ O 0.97, K₂ O 2.43, and others).This sludge slag was pulverized in 200 g portions in a disk mill for 10minutes such that about 9 wt. % of residue was left on a 90 μm sieve. To450 parts by weight of the thus-pulverized material and 450 parts byweight of aggregate having a grain size of 0.5 to 2.38 mm prepared bycoarsely pulverizing the sludge slag, were added 270 parts by weight ofwater glass No. 1 and 22.5 parts by weight of water. The resultingmixture was processed through mixing and curing under conditions similarto those of Example 4-1, thereby obtaining samples of 4-hour, 8-hour,and 16-hour curing at 80° C.

Some 8-hour-cured samples were immersed in 10% hydrochloric acid andsulfuric acid solutions for 7 and 14 days, respectively, to therebyprepare acid-resistance-tested samples.

Example 4-56

A sample was prepared through mixing and curing under conditions similarto those of Example 4-1 except that 150 parts by weight of thepulverized material of polymer-based sludge slag of Example 4-55, 150parts by weight of aggregate having a grain size of 0.5 to 2.38 mmprepared from the polymer-based sludge slag, and 90 parts by weight of asoda aluminate solution (product #2019 manufactured by Asada Kagaku,Co., Ltd.) were used, thereby obtaining samples of 8-hour and 16-hourcuring at 80° C.

Example 4-57

Sludge slag (major chemical composition (wt. %): SiO₂ 46.3, Al₂ O₃ 18.4,Fe₂ O₃ 9.0, CaO 9.4, MgO 3.0, P₂ O₅ 7.7, SO₀₃ 0.0, Na₂ O 1.51, K₂ O1.51, and others) from Metropolitan Tokyo was pulverized in 200 gportions in a disk mill for 10 minutes such that about 8 wt. % ofresidue was left on a 90 μm sieve and about 23 wt. % of residue was lefton a 63 μm sieve (a Blaine value of about 2500 cm² /g). To 600 parts byweight of the thus-pulverized material, were added 180 parts by weightof water glass No. 1 and 36 parts by weight of water. The resultantmixture was mixed in a Hobart mixer. The mixed mixture was charged intoa mold for forming a sample having a size of 2 cm×2 cm×8 cm whilevibration was applied to the mold.

The charged mold was placed in a thermostat-hygrostat chamber(manufactured by Tabai) which was set to a temperature of 20° C.Subsequently, the temperature of the chamber was raised from 20° C. to80° C. over 3 hours at a relative humidity of 98%, and subsequently thechamber was maintained at 80° C. for 4 hours (8 hours) (curing time),thereby obtaining a sample. Some 8-hour-cured samples were immersed in10% hydrochloric acid and sulfuric acid solutions for 7 days to therebyprepare acid-resistance-tested samples.

Example 4-58

97.5 parts by weight of a soda aluminate solution (product #2019manufactured by Asada Kagaku, Co., Ltd.) was added to 300 parts byweight of the pulverized material of polymer-based sludge slag ofExample 4-57. Subsequently, the resulting mixture was processed in amanner similar to that of Example 4-57, thereby obtaining samples of8-hour and 16-hour curing at 80° C.

Example 4-59

A sample was prepared through mixing and curing under conditions similarto those of Example 4-1 except that 150 parts by weight of thepulverized material of polymer-based sludge slag of Example 4-57, 150parts by weight of aggregate having a grain size of 0.5 to 2.38 mmprepared from the polymer-based sludge slag, and 82.5 parts by weight ofa soda aluminate solution (product #2019 manufactured by Asada Kagaku,Co., Ltd.) were used, thereby obtaining samples of 8-hour and 16-hourcuring at 80° C.

Example 4-60

Lime-based sludge-incinerated ashes were melted in an electric furnaceat a temperature of 1550° C. for 1 hour. The resultant melt was pouredinto water to obtain vitric sludge slag (material from SaitamaPrefectural Sewerage Corp. having the following major chemicalcomposition (wt. %): SiO₂ 14.3, Al₂ O₃ 10.6, Fe₂ O₃ 21.7, CaO 41.3, MgO3.8, P₂ O₅ 5.7, SO₃ 0.1, Na₂ O 0.27, K₂ O 0.38, and others). This sludgeslag was pulverized in 200 g portions in a disk mill for 10 minutes suchthat about 9 wt. % of residue was left on a 90 um sieve. To 300 parts byweight of the thus-pulverized material and 300 parts by weight ofaggregate having a grain size of 0.5 to 2.38 mm prepared by coarselypulverizing the sludge slag, were added 180 parts by weight of waterglass No. 1 and 15 parts by weight of water. The resulting mixture wasmixed in a manner similar to that of Example 4-1. However, the mixturebegan to set during mixing, indicating quick-hardening properties. Thus,a sample for strength measurement use was not prepared from the mixture.

An X-ray analysis of the powder revealed that this sludge slag was notcompletely vitrified.

Example 4-61

Crushed stone sludge (material supplied by Aritune Kogyo Co., Ltd.having the following major chemical composition (wt. %): SiO₂ 54.4, Al₂O₃ 18.6, Fe₂ O₃ 6.2, CaO 5.6, MgO 2.8, Na₂ O 3.08, K₂ 0 1.67, andothers) was melted in an electric furnace at temperatures of 1500° C.(for 1 hour) and 1400° C. (for 1 hour). The resultant melt was pouredinto water to obtain vitric crushed-stone sludge slag. A sample wasprepared through mixing and curing under conditions similar to those ofExample 4-1 except that this crushed-stone sludge slag was used, therebyobtaining samples of 4-hour, 8-hour, and 16-hour curing at 80° C. Thesludge slag was pulverized in 200 g portions in a disk mill for 10minutes to a fineness of 2100 cm² /g in Blaine value. To 600 parts byweight of the thus-pulverized material, were added 180 parts by weightof water glass No. 1 and 30 parts by weight of water. The resultingmixture was processed through mixing and curing under conditions similarto those of Example 4-1, thereby obtaining samples of 4-hour, 8-hour,and 16-hour curing at 80° C.

Example 4-62

The pulverized material of crushed-stone sludge slag of Example 4-61 wasused to prepare a sample through mixing and curing under conditionssimilar to those of Example 4-61 except that 180 parts by weight ofwater glass No. 3 as alkali silicate was added to 600 parts by weight ofthe pulverized material, thereby obtaining samples of 4-hour, 8-hour,and 16-hour curing at 80° C.

Example 4-63

The pulverized material of crushed-stone sludge slag of Example 4-61 anda soda aluminate solution (product #2019 manufactured by Asada Kagaku,Co., Ltd.) as alkali aluminate were used to prepare a sample throughmixing and curing under conditions similar to those of Example 4-61,thereby obtaining samples of 4-hour, 8-hour, and 16-hour curing at 80°C.

Comparative Example 4-1

Each of the pulverized materials of refuse slag of Examples 4-1, 4-11,4-16, 4-19, and 4-27 was used to prepare a mixed mixture under mixingconditions similar to those of Example 3-1 (however, alkali silicate andalkali aluminate were not used). The thus-mixed mixture underwentforming in a manner similar to that of Example 4-1, followed by curingfor 4 to 16 hours at 80° C. However, none of the thus-prepared samplesset.

Comparative Example 4-2

100 g of incineration ashes, which precede refuse slag and sludge slagof corresponding Examples, was placed in each of a plurality of beakers.Various mixtures of 30 parts by weight of soda silicate No. 1 or sodaaluminate (product #2019 manufactured by Asada Kagaku Kogyo, Co., Ltd)and water ranging in content from 5 to 60 parts by weight were mixed.Through use of these materials, samples were prepared through curing for4 to 16 hours at 80° C. in a manner similar to that of Example 3-1.

Samples prepared from refuse-incinerated ashes (fly ashes) of KumagayaCity and sludge-incinerated ashes did not set. On the other hand,samples prepared from refuse-incinerated ashes of Yokohama City andrefuse-incinerated ashes (principal ashes) of Kumagaya City somewhatset, but merely to such an extent that the hardened products can bebroken with a hand.

Comparative Example 4-3

The pulverized material of lime-based sludge slag of Example 4-44 wasused to prepare a mixed mixture under mixing conditions similar to thoseof Example 4-44 (however, alkali silicate was not used). The thus-mixedmixture underwent forming in a manner similar to that of Example 4-1,followed by curing for 4 to 16 hours at 80° C. However, thethus-prepared sample did not set.

Comparative Example 4-4

Sludge-incinerated ashes, which precede the lime-based sludge slag ofExample 4-44, and polymer-based sludge-incinerated ashes of Example 4-56were used. 100 parts by weight of each kind of these ashes was placed ineach of a plurality of beakers. Various mixtures of 30 parts by weightof each of water glass No. 1 and soda aluminate and water ranging incontent from 5 to 60 parts by weight were Mixed. Through use of thesematerials, samples were prepared through curing for 4 to 16 hours at 80°C. in a manner similar to that of Example 4-1. The thus-prepared samplesdid not set.

The chemical composition of refuse- and sludge-incinerated ashes is notmuch different from that of vitrified slag produced from these ashes,except for those components such as S and Cl components which are highlylikely to vaporize during slagging, and heavy metal such as lead. Aconceivable reason for absence of hardening through reaction with alkalisilicate or alkali aluminate is that compounds which constituteincineration ashes are in a

Refuse-incinerated ashes of Yokohama City and refuse-incinerated ashes(principal ashes) of Kumagaya City shown in the Comparative Example hasa property of somewhat setting when mixed with alkali silicate or alkalialuminate. A conceivable reason for this is that theserefuse-incinerated ashes may contain some fused substance andwater-soluble substances such as salts and chlorides, which may impart acertain setting property. However, hardened products obtained from theincineration ashes are not strong enough to endure actual use.

In the above-described Examples, an electric furnace is set to atemperature at least 50° to 100° C. higher than a lowest meltingtemperature in order to accelerate a melting process and to readily pourout a molten substance from its container. Further, it is confirmed thateven when an incineration substance is melted at its lowest meltingtemperature, the substance becomes a good hardening material if it isvitrified.

Tables 8 to 12 show measurements of compressive strength for samplesobtained in the above-described Examples 4-1 to 4-63.

                                      TABLE 8                                     __________________________________________________________________________                                     Formulation       Curing Conditions                                           (parts by weight) (°C.-hours or                                                          days)                      Composition of slag (wt. %)          Slag          strength                   SiO.sub.2                                                                           CaO                                                                              Al.sub.2 O.sub.3                                                                  Fe.sub.2 O.sub.3                                                                  MgO R.sub.2 O                                                                        P.sub.2 O.sub.5                                                                  Cl C/S                                                                              powder                                                                            agg. Stimul.                                                                            Water                                                                             (kgf/cm.sup.2)             __________________________________________________________________________    Ex.                                                                              39.1                                                                             20.3                                                                             15.6                                                                              12.3                                                                              3.3 4.11                                                                             1.7                                                                              0.2                                                                              0.56                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-1                              600      180  30  1117                                                                              1238                                                                              1318               Ex.                                                                              "                          0.56                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-2                              600      180       263                                                                               463                                                                               607               Ex.                                                                              "                          0.56                                                                             Pulv.    No. 1    20° C.                                                                     20° C.          4-3                              600      180  30  3 days                                                                            3 days                                                                    673 799                    Ex.                                                                              "                          0.56                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-4                              200 200  120  10   700                                                                               748                                                                               792               Ex.                                                                              "                          0.56                                                                             Pulv.                                                                             Agg. No. 3    80-4                                                                              80-8                                                                              80-16              4-5                              200 200  120       68  194                                                                               359               Ex.                                                                              "                          0.56                                                                             Pulv.                                                                             Agg. #2019    80-4                                                                              80-8                                                                              80-16              4-6                              200 200  120       269                                                                               305                                                                               473               Ex.                                                                              "                          0.56                                                                             Pulv.                                                                             Agg. #1219    80-4                                                                              80-8                                                                              80-16              4-7                              200 200  120       136                                                                               176                                                                               191               Ex.                                                                              35.1                                                                             27.2                                                                             14.4                                                                              11.9                                                                              2.9 3.39                                                                             1.5   0.83                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-8                              600      180  30  1169                                                                              1447                                                                              1643               Ex.                                                                              "                          0.83                                                                             Pulv.    No. 1    3 days                                                                            7                                                                                 28 days            4-9                              600      180  30   560                                                                               643                                                                               956               Ex.                                                                              "                          0.83                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-10                             600      180       364                                                                               538                                                                               611               Ex.                                                                              31.5                                                                             34.4                                                                             13.3                                                                              10.3                                                                              2.7 2.71                                                                             1.4   1.17                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-11                             600      180  30  1443                                                                              1615                                                                              1716               Ex.                                                                              "                          1.17                                                                             Pulv.    No. 1    3 days                                                                            7                                                                                 28 days            4-12                             600      180  30   673                                                                               799                                                                              1025               Ex.                                                                              "                          1.17                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-13                             600      180       765                                                                              1134                                                                              1281               Ex.                                                                              27.4                                                                             39.0                                                                             18.2                                                                              8.1 2.1 2.14                                                                             1.2   1.52                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-14                             600      180  30  1070                                                                              1231                                                                              1289               Ex.                                                                              21.9                                                                             40.7                                                                             24.0                                                                              6.7 1.8 1.83                                                                             0.9   1.99                                                                             Immediately set.                             4-15                             Sampled could not                                                             be prepared.                                 __________________________________________________________________________

                                      TABLE 9                                     __________________________________________________________________________    Ex.                                                                              54.3                                                                             7.7                                                                              17.9                                                                              6.8 3.5 4.73                                                                             0.4   0.15                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-16                             600      180  30  351 482 553                Ex.                                                                              "                          0.15                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-17                             600      180       54 112 162                Ex.                                                                              "                          0.15                                                                             Pulv.    #2019    80-4                                                                              80-8                                                                              80-16              4-18                             600      120      190 291 367                Ex.                                                                              36.6                                                                             23.4                                                                             17.7                                                                              5.9 3.8 5.24                                                                             3.5   0.68                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-19                             200 200   20  36   75 145 168                Ex.                                                                              "                          0.68                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-20                             200 200   40  32  528 770 919                Ex.                                                                              "                          0.68                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-21                             200 200   80  16  650 793 869                Ex.                                                                              "                          0.68                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-22                             200 200  120  8   602 645 669                Ex.                                                                              "                          0.68                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-23                             200 200  200      375 416 393                Ex.                                                                              "                          0.68                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-24                             200 200  400      144 154 110                Ex.                                                                              "                          0.68                                                                             Pulv.                                                                             Agg. No. 3    80-4                                                                              80-8                                                                              80-16              4-25                             200 200   80       62 224 428                Ex.                                                                              "                          0.68                                                                             Pulv.                                                                             Agg. #2019    80-4                                                                              80-8                                                                              80-16              4-26                             200 200   80      349 456 584                Ex.                                                                              30.6                                                                             30.9                                                                             19.1                                                                              2.0 5.6 2.01                                                                             2.2   0.92                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-27                             600      180  30  934 1202                                                                              1372               Ex.                                                                              "                          0.92                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-28                             600      180       97 325 424                Ex.                                                                              "                          0.92                                                                             Pulv.    #2019    80-4                                                                              80-8                                                                              80-16              4-29                             600      180      951 1117                                                                              1275               Ex.                                                                              34.1                                                                             26.3                                                                             17.5                                                                              5.0 4.1 2.91                                                                             3.1                                                                              -- 0.83                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-30                             200 200   90  10  801 895 1275               Ex.                                                                              "                          0.83                                                                             Pulv.                                                                             Agg. No. 3    80-4                                                                              80-8                                                                              80-16              4-31                             200 200   90       63 194 353                Ex.                                                                              "                          0.83                                                                             Pulv.                                                                             Agg. #2019    80-4                                                                              80-8                                                                              80-16              4-32                             200 200   90      473 494 722                Ex.                                                                              54.6                                                                             17.6                                                                             9.7 3.1 2.0 8.87                                                                             1.7                                                                              0.1                                                                              0.35                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-33                             600      180  30   45 131 129                __________________________________________________________________________

                                      TABLE 10                                    __________________________________________________________________________    Ex.                                                                              54.6                                                                             17.6                                                                             9.7 3.1 2.0 8.87                                                                             1.7                                                                              0.1                                                                              0.35                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-34                             600      180      164 163 224                Ex.                                                                              "                          0.35                                                                             Pulv.    #2019    80-4                                                                              80-8                                                                              80-16              4-35                             600      180      181 144 191                Ex.                                                                              54.6                                                                             7.7                                                                              18.1                                                                              6.7 3.5 4.73                                                                             0.4                                                                              0.0                                                                              0.15                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-36                             600      180  30  328 519 645                Ex.                                                                              "                          0.15                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-37                             600      180       65 163 323                Ex.                                                                              "                          0.15                                                                             Pulv.    #2019    80-4                                                                              80-8                                                                              80-16              4-38                             600      180      181 144 191                Ex.                                                                              36.6                                                                             21.5                                                                             18.8                                                                              8.2 3.7 4.57                                                                             2.5                                                                              0.3                                                                              0.63                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-39                             800      540  90  186 189 213                Ex.                                                                              "                          0.63                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-40                             800      540       22  36  85                Ex.                                                                              "                          0.63                                                                             Pulv.    #2019    80-4                                                                              80-8                                                                              80-16              4-41                             800      540      134 147 189                Ex.                                                                              37.1                                                                             19.3                                                                             14.9                                                                              11.6                                                                              3.1 7.34                                                                             1.5                                                                              F  0.56                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-42                       2.1   600      180      148 418 546                Ex.                                                                              31.0                                                                             26.5                                                                             12.6                                                                              9.7 2.6 3.23                                                                             9.6                                                                              -- 0.92                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-43                             600      180      743 811 834                Ex.                                                                              33.4                                                                             33.9                                                                             14.2                                                                              5.0 2.4 1.85                                                                             7.0                                                                              -- 1.08                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-44                             900      270  45  458 659 1257                                                    Immersion in  7 days                                                                              14 days                                                   10% HCl       352   476                                                       Immersion in  7 days                                                                              14 days                                                   10% H.sub.2 SO.sub.4                                                                        317   502                  Ex.                                                                              "                          1.08                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-45                             900      270      153 222 395                                                     Immersion in  7 days                                                                              14 days                                                   10% HCl       148   266                                                       Immersion in  7 days                                                                              14 days                                                   10% H.sub.2 SO.sub.4                                                                        176   240                  Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-46                             200 200   20  32  313 651 673                Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-47                             200 200   40  24  628 1066                                                                              1064               Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-48                             200 200   80  16  739 905 1075               __________________________________________________________________________

                                      TABLE 11                                    __________________________________________________________________________    Ex.                                                                              33.4                                                                             33.9                                                                             14.2                                                                              5.0 2.4 1.85                                                                             7.0                                                                              -- 1.08                                                                             Pulv.                                                                             Agg. No. 3    80-4                                                                              80-8                                                                              80-16              4-49                             300  300 180  7.5 396 775 941                Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-50                             200  200 200      393 458 476                Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-51                             200  200 400      131 133 124                Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    Curing in humid            4-52                             900  900 450  40  environment                                                                   (20° C.)                                                               3 days                                                                            7                                                                                 28 days                                                               167 353 525                Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    Curing in water            4-53                             900  900 450  40  (° C.)                                                                 14 days                                                                             28 days                                                                 395   539                  Ex.                                                                              "                          1.08                                                                             Pulv.                                                                             Agg. No. 1    Curing in humid            4-54                             630 1170 297  60  environment                                                                   (20° C.)                                                               3 days                                                                            7                                                                                 28 days                                                               216 359 548                Ex.                                                                              29.6                                                                             10.0                                                                             16.6                                                                              13.4                                                                              3.5 3.38                                                                             20.4                                                                             -- 0.34                                                                             Pulv.                                                                             Agg. No. 1    80-4                                                                              80-8                                                                              80-16              4-55                             450  450 270  22.5                                                                              553 561 591                                                     Immersion in  7 days                                                                              14 days                                                   10% HCl       236   381                                                       Immersion in  7 days                                                                              14 days                                                   10% H.sub.2 SO.sub.4                                                                        231   440                  Ex.                                                                              "                          0.34                                                                             Pulv.                                                                             Agg. #2019    80-4                                                                              80-8                                                                              80-16              4-56                             150  150  90      --   34 129                Ex.                                                                              46.3                                                                             9.4                                                                              18.4                                                                              9.0 3.0 3.02                                                                             7.7                                                                              -- 0.20                                                                             Pulv.    No. 1    80-4                                                                              80-8                   4-57                             600      180  36  481 519                                                         Immersion in  7 days                                                          10% HCl       510                                                             Immersion in  7 days                                                          10% H.sub.2 SO.sub.4                                                                        500                        Ex.                                                                              "                          0.20                                                                             Pulv.    #2019    80-4                                                                              80-8                                                                              80-16              4-58                             300       97.5        176 212                Ex.                                                                              "                          0.20                                                                             Pulv.                                                                             Agg. #2019    80-4                                                                              80-8                                                                              80-16              4-59                             150  150  82.5        133 355                Ex.                                                                              300td                                                                            41.3                                                                             10.6                                                                              21.7                                                                              3.8 0.65                                                                             5.7                                                                              -- 3.09                                                                             Pulv.                                                                             Agg. No. 3    Quick setting              4-60                                                                             14.3                          300  300 180  15                             Ex.                                                                              Chemical composition of crushed stone sludge                                                             0.15                                                                             Pulv.    No. 1    80-4                                                                              80-8                                                                              80-16              4-61                                                                             54.3                                                                             7.7                                                                              17.9                                                                              6.8 3.5 4.53                                                                             0.4                                                                              --    600      180  30  328 519 645                __________________________________________________________________________

                                      TABLE 12                                    __________________________________________________________________________    Ex.                                                                              Chemical composition of crushed stone sludge                                                             0.15                                                                             Pulv.    No. 3    80-4                                                                              80-8                                                                              80-16              4-62                                                                             54.3                                                                             7.7                                                                              17.9                                                                              6.8 3.5 4.53                                                                             0.4                                                                              --    600      180       65 163 323                Ex.                                                                              "                          0.15                                                                             Pulv.    #2019    80-4                                                                              80-8                                                                              80-16              4-63                             600      180      170 366 455                __________________________________________________________________________

As is apparent from Tables 8 to 12, a variety of fused slags producedfrom refuse-incinerated substances or from incinerated swage sludge andindustrial watstes such as crushed stone sludge can be prepared into aslag composition of the present invention, and when the resultant slagcomposition is combined with an alkaline activator such as water glass,sodium aluminate, or sodium silicate so as to form a hardeningcomposition of the present invention, it is possible to obtain ahardened product having excellent strength through a simple procedure ofmixing with water and curing the resultant mixture.

As shown in Examples 4-44, 4-45, 4-55, and 4-57, the hardened productsof the present invention, particularly the hardened products which madeuse of alkali silicate exhibited quite excellent resistance againstacids.

Although no comparative data are shown in terms of the resistanceagainst acids, comparative test were performed by use of mortar samples,each having a size of 2 cm×2 cm×2 cm, which had been prepared inaccordance with the JIS method for preparing samples for testingstrength of mortar of portland cement, after curing at 80° C. for 8hours. The samples that were immersed in 10% HCl collasped in 1-2 days,and those immersed in 10% H₂ SO₄ collapsed after passage of 7 days, andtherefore, their strength could not be measured.

Example 5-1

Lime-based sludge slag (material from Osaka Municipal Sewerage Corp.having the following major chemical composition (wt. %): SiO₂ 33.4, Al₂O₃ 14.2, Fe₂ O₃ 5.0, CaO 33.9, MgO 2.4, P₂ O₅ 7.0, S 1.1, Na₂ O 0.75, K₂O 0.68, and others) (C/S=1.10) was pulverized in a ball mill so as toobtain samples having pulverized degrees by Blaine value of 3,500 and4,500 cm² /g. To each sample (5 parts by weight) was added 95 parts byweight of ordinary portland cement of Chichibu-Onoda brand, to therebyprepare a cement composition. The SO₃ content of the mixed cements wasadjusted to 2 wt. % for samples having a Blaine value of 3,500 cm² /g,and to 2 wt. % or 3 wt. % for samples having a Blaine value of 4,500 cm²/g. Thus, three different kinds of mixed cement samples were obtained.These mixed cements, through use of ISO standard sand, were mixed andmolded in accordance with the ISO test method for determining mortarstrength (cement: sand=1:3, water-cement ratio: 50%, 4 cm ×4 cm×16 cm).The resultant product was cured for one day in a humid atmosphere at 20°C. Thereafter, the mold was removed, followed by curing in water.Compressive strength of each sample was measured on day 3, 7, 28, and91. The finally cured product was subjected to an X-ray analysis, tothereby obtain the residual amount of Ca(OH)₂.

Example 5-2

The procedure of Example 5-1 was repeated, except that the crushedsludge slag product of Example 5-1 was used in amounts of 20 parts byweight and ordinary portland cement was used in amounts of 80 parts byweight, to thereby determine the compressive strength on day 3, 7, 28,and 91. Also, the amount of Ca(OH)₂ remaining in the hardened productwas checked.

Example 5-3

The procedure of Example 5-1 was repeated, except that the crushedsludge slag product of Example 5-1 was used in amounts of 40 parts byweight and ordinary portland cement was used in amounts of 60 parts byweight, to thereby determine the compressive strength on day 3, 7, 28,and 91. Also, the amount of Ca(OH)₂ remaining in the hardened productwas checked.

Example 5-4

The procedure of Example 5-1 was repeated, except that the crushedsludge slag product of Example 5-1 was replaced by 5 parts by weight ofpolymer-based sludge-incinerated fused slag (major chemical composition(wt. %): SiO₂ 46.3, Al₂ O₃ 18.4, Fe₂ O₃ 9.0, CaO 9.4, MgO 3.0, P₂ O₅14.1, Na₂ O 1.37, K₂ O 2.69, and others) (C/S=0.21) from MetropolitanTokyo, and that the amount of ordinary cement was 95 parts by weight, tothereby determine the compressive strength on day 3, 7, 28, and 91.Also, the amount of Ca(OH)₂ remaining in the hardened product waschecked.

Example 5-5

The procedure of Example 5-1 was repeated, except that thesludge-incinerated fused slag of Example 5-4 was used in amounts of 20parts by weight and ordinary portland cement was used in amounts of 80parts by weight, to thereby determine the compressive strength on day 3,7, 28, and 91.

Example 5-6

The procedure of Example 5-1 was repeated, except that thesludge-incinerated fused slag of Example 5-4 was used in amounts of 40parts by weight and ordinary portland cement was used in amounts of 60parts by weight, to thereby determine the compressive strength on day 3,7, 28, and 91. Also, the amount of Ca(OH)₂ remaining in the hardenedproduct was checked.

Example 5-7

The procedure of Example 5-1 was repeated, except that the crushedsludge slag product of Example 5-1 was replaced by 5 parts by weight offused slag produced from refuse-incinerated substances (major chemicalcomposition (wt. %): SiO₂ 38.1, Al₂ O₃ 17.2, Fe₂ O₃ 12.1, CaO 19.6, MgO3.2, SO₃ 0.6, Na₂ O 2.61, K₂ O 1.34, TiO₂ 1.74, P₂ O₅ 1.6, and others)(C/S=0.53) which had been poured into water for quenching, and that theamount of ordinary cement was 95 parts by weight, to thereby determinethe compressive strength on day 3, 7, 28, and 91 (for the sample havinga Blaine value of 4,500 cm² /g only). The amount of Ca(OH)₂ remaining inthe hardened product was also checked. The fused slag produced fromrefuse-incinerated substances used in this test was prepared by placingrefuse-incinerated ashes of Yokohama City in an alumina container,melting the ashes in an electric furnace for 1 hour at 1,400° C., andthen pouring the melt into water for quenching.

Example 5-8

The procedure of Example 5-1 was repeated, except that therefuse-incinerated fused slag of Example 5-7 was used in amounts of 20parts by weight and ordinary portland cement was used in amounts of 80parts by weight, to thereby determine the compressive strength on day 3,7, 28, and 91 (for the sample having a Blaine value of 4,500 cm² /gonly). The amount of Ca(OH)₂ remaining in the hardened product was alsochecked.

Example 5-9

The procedure of Example 5-1 was repeated, except that therefuse-incinerated fused slag of Example 5-7 was used in amounts of 40parts by weight and ordinary portland cement was used in amounts of 60parts by weight, to thereby determine the compressive strength on day 3,7, 28, and 91 (for the sample having a Blaine value of 4,500 cm² /gonly). The amount of Ca(OH)₂ remaining in the hardened product was alsochecked.

Example 10

The procedure of Example 5-1 was repeated, except that therefuse-incinerated fused slag of Example 5-7 was replaced by 5 parts byweight of fused slag produced from refuse-incinerated substances (majorchemical composition (wt. %): SiO₂ 36.6, Al₂ O₃ 18.8, Fe₂ O₃ 8.2, CaO21.5, MgO 3.7, Na₂ O 3.24, K₂ O 1.33, P₂ O₅ 2.6, and others) (C/S=0.60)from Yoshikawa City (previously called "Yoshikawa-machi") in SaitamaPrefecture, and that the amount of ordinary cement was 95 parts byweight, to thereby determine the compressive strength on day 3, 7, 28,and 91 (for the sample having a Blaine value of 4,500 cm_(2/) g only).The amount of Ca(OH)₂ remaining in the hardened product was alsochecked.

Example 5-11

The procedure of Example 5-1 was repeated, except that therefuse-incinerated fused slag of Example 5-10 was used in amounts of 20parts by weight and ordinary portland cement was used in amounts of 80parts by weight, to thereby determine the compressive strength on day 3,7, 28, and 91. The amount of Ca(OH)₂ remaining in the hardened productwas also checked.

Example 5-12

The procedure of Example 5-1 was repeated, except that therefuse-incinerated fused slag of Example 5-10 was used in amounts of 40parts by weight and ordinary portland cement was used in amounts of 60parts by weight, to thereby determine the compressive strength on day 3,7, 28, and 91 (for the sample having a Blaine value of 4,500 cm² /gonly). The amount of Ca(OH)₂ remaining in the hard hardened product wasalso checked.

Example 5-25

The procedure of Example 5-1 was repeated, except that the followingwere used: crushed slag product of Example 5-1 5 parts by weight; blastfurnace slag provided by Nippon Kokan K. K. 15 parts by weight; ordinaryportland cement 80 parts by weight; and SO₃ 3 wt. %. The compressivestrength of the resultant sample was determined.

Comparative Example 5-1

The procedure of Example 5-1 was repeated, except that thesludge-incinerated fused slag of Example 5-1 was replaced by 5 parts byweight of fused slag blast furnace slag of Nippon Kokan K. K. (majorchemical composition: SiO₂ 32.2 wt. %, CaO 41.3 wt. %, Al₂ O₃ 15.0 wt.%, Fe₂ O₃ 1.0 wt. %, MgO 7.8 wt. %, N) (C/S =1.37), which had beencrushed, and that the amount of ordinary cement was 95 parts by weight,to thereby determine the compressive strength on day 3, 7, 28, and 91.The amount of Ca(OH)₂ remaining in the hardened product was alsochecked.

Comparative Example 5-2

The procedure of Example 5-1 was repeated, except that the blast furnaceslag of Example 5-1 was used in amounts of 20 parts by weight andordinary portland cement was used in amounts of 40 parts by weight, tothereby determine the compressive strength on day 3, 7, 28, and 91.

Comparative Example 5-3

The procedure of Example 5-1 was repeated, except that the blast furnaceslag of Example 5-1 was used in amounts of 40 parts by weight andordinary portland cement was used in amounts of 60 parts by weight, tothereby determine the compressive strength on day 3, 7, 28, and 91. Theamount of Ca(OH)₂ remaining in the hardened product was also checked.

Comparative Example 5-4

The procedure of Example 5-1 was repeated through sole use of ordinaryportland cement, to thereby determine the compressive strength on day 3,7, 28, and 91. The amount of Ca(OH)₂ remaining in the hardened productwas also checked.

Example 5-13

A sample was prepared through use of special grade chemicalsmanufactured by Kanto Kagaku Co., Ltd. so that the sample had thefollowing composition: SiO₂ 50 wt. %, CaO 0 wt. %, Al₂ O₃ 30 wt. %, Fe₂O₃ 5 wt. %, MgO 5 wt. %, P₂ O₅ 5 wt. %, and Na₂ O 5 wt. % (C/S=0). Thesample was heated to melt at 1,370° C. for 60 minutes, at 1,420° C. for60 minutes, and at 1,520° C. for 20 minutes. Subsequently, the samplewas poured into water for quenching to thereby obtain a fused slag.

The fused slag was pulverized in a ball mill to have a pulverized degreeexpressed by Blaine value of 3,000 cm² /g, and 20 parts by weight of theresultant pulverized slag were mixed with 80 parts by weight of ordinaryportland cement of "Chichibu-Onoda" brand, to thereby obtain a mixedcement composition.

The SO₃ content in the amount of the mixed cement was adjusted to be 2%by use of natural gypsum. The mixed cement, through use of ISO standardsand, was mixed and molded in accordance with the ISO test method fordetermining mortar strength (cement: sand=1:3, water-cement ratio: 50%,4 cm×4 cm×16 cm). The resultant product was placed in a steam curingapparatus (manufactured by Tabai), and the temperature of the apparatuswas elevated from room temperature to 80° C. over while maintaining ahumid atmosphere. The product was cured for 12 hours in the apparatus,and was cooled to room temperature over 2 hours. The cooled product wasremoved from the mold and its strength was measured.

Example 5-14

The procedure of Example 5-13 was repeated, except that 40 parts byweight of the fused slag of Example 5-13 and 60 parts by weight ofordinary portland cement were used, to thereby determine the compressivestrength of the sample.

Example 5-15

A sample was prepared through use of special grade chemicalsmanufactured by Kanto Kagaku Co., Ltd. so that the sample had thefollowing composition: SiO2 60 wt. %, CaO 0 wt. %, Al₂ O₃ 20 wt. %, Fe₂O₃ 5 wt. %, MgO 5 wt. %, Na₂ O 5 wt. %, P₂ O₅ 5 wt. %, and F 2.5 wt. %(adjusted by use of NaF). The sample was heated to melt at 1,300° C. for60 minutes, at 1,400° C. for 30 minutes, and at 1,500° C. for 20minutes. Subsequently, the sample was poured into water for quenching tothereby obtain a fused slag. The fused slag was processed in a mannersimilar to that described in Example 5-13, and its compressive strengthwas measured.

Example 5-16

The procedure of Example 5-13 was repeated, except that fused slag ofExample 5-21 was used in different degrees of pulverization, each in anamount of 40 parts by weight, and that 60 parts by weight of ordinaryportland cement were used, to thereby determine the compressive strengthof the sample.

Example 5-17

A sample was prepared through use of special grade chemicalsmanufactured by Kanto Kagaku Co., Ltd. so that the sample had thefollowing composition: SiO₂ 65 wt. %, CaO 0 wt. %, Al₂ O₃ 15 wt. %, Fe₂O₃ 5 wt. %, MgO 5 wt. %, Na₂ O 0 wt. %, and F 2.5 wt. % (adjusted by useof NaF). The sample (C/S=0) was heated to melt at 1,300° C. for 1 hour,at 1,400° C. for 60 minutes, and at 1,500° C. for 20 minutes.Subsequently, the sample was poured into water for quenching to therebyobtain a fused slag. The fused slag was processed in a manner similar tothat described in Example 5-13, and its compressive strength wasmeasured.

Example 5-18

The procedure of Example 5-13 was repeated, except that 40 parts byweight of fused slag of Example 5-17 which had been crushed and 60 partsby weight of ordinary portland cement were used, to thereby determinethe compressive strength of the sample.

Example 5-19

A sample was prepared through use of special grade chemicalsmanufactured by Kanto Kagaku Co., Ltd. so that the sample had thefollowing composition: SiO₂ 85 wt. %, CaO 0 wt. %, Al₂ O₃ 0 wt. %, Fe₂O₃ 10 wt. %, and Na₂ O 5 wt. %. The sample (C/S=0) was heated to melt at1,500° C. for 1 hour, at 1,550° C. for 40 minutes, and at 1,580° C. for20 minutes. Subsequently, the sample was poured into water for quenchingto thereby obtain a fused slag.

The fused slag was pulverized in a ball mill to have a pulverized degreeexpressed by Blaine value of 4,500 cm² /g, and 20 parts by weight of theresultant pulverized slag were mixed with 80 parts by weight of ordinaryportland cement of "Chichibu-Onoda" brand, to thereby obtain a mixedcement composition. The composition was processed in a manner similar tothat described in Example 5-13, and its compressive strength wasmeasured.

Example 5-20

The procedure of Example 5-13 was repeated, except that 40 parts byweight of fused slag of Example 5-19 which had been crushed and 60 partsby weight of ordinary portland cement were used, to thereby determinethe compressive strength of the sample.

Example 5-21

A sample was prepared through use of special grade chemicalsmanufactured by Kanto Kagaku Co., Ltd. so that the sample had thefollowing composition: SiO₂ 90 wt. %, CaO 0 wt. %, Al₂ O₃ 0 wt. %, Na₂ O5 wt. %, and F 5 wt. % (adjusted by use of NaF). The sample (C/S=0) washeated to melt at 1,500° C. for 60 minutes, at 1,550° C. for 60 minutes,and at 1,580° C. for 20 minutes. Subsequently, the sample was pouredinto water for quenching to thereby obtain a fused slag, and itscompressive strength was measured.

Example 5-22

The procedure of Example 5-19 was repeated, except that 40 parts byweight of fused slag of Example 5-21, which had been crushed, and 60parts by weight of ordinary portland cement were used, to therebydetermine the compressive strength of the sample.

Example 5-23

A sample was prepared through use of special grade chemicalsmanufactured by Kanto Kagaku Co., Ltd. so that the sample had thefollowing composition: SiO₂ 50 wt. %, CaO 0 wt. %, Al₂ O₃ 0 wt. %, Fe₂O₃ 10 wt. %, MgO 15 wt. %, and Na₂ O 15 wt. % (C/S=0). The sample washeated to melt at 1,200° C. for 1 hour and at 1,300° C. for 1 hour.Subsequently, the sample was poured into water for quenching to therebyobtain a fused slag.

The fused slag was pulverized in a ball mill to have a pulverized degreeexpressed by Blaine value of 4,500 cm² /g, and 20 parts by weight of theresultant pulverized slag were mixed with 80 parts by weight of ordinaryportland cement of "Chichibu-Onoda" brand, to thereby obtain a mixedcement composition. The composition was processed in a manner similar tothat described in Example 5-13, and the compressive strength of thecomposition was measured.

Example 5-24

The procedure of Example 5-13 was repeated, except that the crushed slagproduct of Example 5-23 was used in amounts of 40 parts by weight andordinary portland cement was used in 60 parts by weight. The compressivestrength of the sample after being cured with steam was determined.

Comparative Example 5-5

The procedure of Example 5-13 was repeated through sole use of ordinaryportland cement, to thereby determine the compressive strength of thesample after being cured with steam. The amount of Ca(OH)₂ remaining inthe hardened product was also checked.

Comparative Example 5-6

The procedure of Example 5-13 was repeated, except that the fused slagof Example 5-21 was replaced by ISO standard sand that had been crushedin a ball mill so as to have a Blaine value of 4,500 cm² /g, and 20parts by weight of the crushed sand was mixed with 80 parts by weight ofordinary portland cement of "Chichibu-Onoda" brand, to thereby obtain acement mixture composition. The compressive strength of the compositionwas determined in a manner similar to that described in Example 5-13.

Comparative Example 5-7

The procedure of Example 5-13 was repeated except that 40 parts byweight of the crushed standard sand described in Comparative Example 5-6and 60 parts by weight of ordinary portland cement were used, to therebydetermine the compressive strength of the sample after being cured withsteam.

The compressive strength of each of the samples obtained in Examples 5-1through 5-25 and Comparative Example 5-1 through 5-7 was measured. Table13 shows the data obtained for the cases in which the Blaine value ofthe slags used was 3,500 cm² /g, and Table 14 shows the data obtainedfor the cases in which the Blaine value of the slags used was 4,500 cm²/g. Table 15 shows the results obtained when the samples were cured withsteam.

                                      TABLE 13                                    __________________________________________________________________________             Slag composition (wt. %)    Compressive                                                                Ratio                                                                            Strength                                 CO.sub.3 (%)                      by (kgf/cm.sup.2).sup.a)                         in                   Na.sub.2 O                                                                          F mol                                                                              day                                                                              day                                                                              day                                                                              day                             Ex. No.                                                                            cement                                                                            SiO.sub.2                                                                        CaO                                                                              Al.sub.2 O.sub.3                                                                  Fe.sub.2 O.sub.3                                                                  MgO                                                                              K.sub.2 O                                                                        P.sub.2 O.sub.5                                                                  Cl                                                                              C/S                                                                              3  7  28 91 Ca(OH).sub.2 .sup.b)         __________________________________________________________________________    Ex. 5-1                                                                            2.0 33.4                                                                             33.9                                                                             14.2                                                                              5.0 2.4                                                                              1.43                                                                             7.0                                                                              0.0                                                                             1.10                                                                             296                                                                              414                                                                              604                                                                              690                                                                              ⊚             Ex. 5-2                                                                            "   "  "  "   "   "  "  "  " "  248                                                                              385                                                                              593                                                                              720                                                                              ◯                Ex. 5-3                                                                            "   "  "  "   "   "  "  "  " "  180                                                                              263                                                                              472                                                                              662                                                                              Δ                      Ex. 5-4                                                                            "   46.3                                                                              9.4                                                                             18.4                                                                              9.0 3.0                                                                              4.09                                                                             14.1                                                                             0.0                                                                             0.21                                                                             291                                                                              473                                                                              603                                                                              718                                                                              ◯                Ex. 5-5                                                                            "   "  "  "   "   "  "  "  " "  249                                                                              384                                                                              553                                                                              728                                                                              Δ                      Ex. 5-6                                                                            "   "  "  "   "   "  "  "  " "  155                                                                              233                                                                              328                                                                              373                                                                              X                            Ex. 5-7                                                                            "   38.1                                                                             19.6                                                                             17.2                                                                              12.1                                                                              3.2                                                                              3.95                                                                             1.6                                                                              0.2                                                                             0.53                                                                             291                                                                              426                                                                              618                                                                              -- ⊚             Ex. 5-8                                                                            "   "  "  "   "   "  "  "  " "  260                                                                              384                                                                              576                                                                              -- Δ                      Ex. 5-9                                                                            "   "  "  "   "   "  "  "  " "  186                                                                              249                                                                              377                                                                              -- X                            Ex. 5-10                                                                           "   36.6                                                                             21.5                                                                             18.8                                                                              8.2 3.7                                                                              4.57                                                                             2.6                                                                              0.3                                                                             0.63                                                                             290                                                                              451                                                                              623                                                                              -- ◯                Ex. 5-11                                                                           "   "  "  "   "   "  "  "  " "  224                                                                              342                                                                              557                                                                              -- Δ                      Ex. 5-12                                                                           "   "  "  "   "   "  "  "  " "  138                                                                              209                                                                              330                                                                              -- X                            C. Ex. 5-1                                                                         "   32.2                                                                             41.3                                                                             15.0                                                                              1.0 7.8                                                                              -- -- --                                                                              1.37                                                                             286                                                                              423                                                                              602                                                                              688                                                                              ⊚             C. Ex. 5-2                                                                         "   "  "  "   "   "  "  "  " "  253                                                                              422                                                                              620                                                                              715                                                                              ◯                C. Ex. 5-3                                                                         "   "  "  "   "   "  "  "  " "  195                                                                              332                                                                              589                                                                              684                                                                              □                 C. Ex. 5-4                                                                         "   (Ordinary portland cement)  282                                                                              454                                                                              626                                                                              716                                                                              ⊚             __________________________________________________________________________     (Note)                                                                        1) Pulverized degree of slag (Blaine value): 3500 cm.sup.2 /g                 .sup.a) Compressive strength of mortar after being cured in water             .sup.b) Amounts of remaining Ca(OH).sub.2                                     ⊚ Considerably great amount                                    ◯ Great amount                                                    □ Small amount                                                     Δ Very small amount                                                     X None                                                                   

                                      TABLE 14                                    __________________________________________________________________________             Slag composition (wt. %)    Compressive                                                                Ratio                                                                            Strength                                 CO.sub.3 (%)                      by (kgf/cm.sup.2).sup.a)                         in                   Na.sub.2 O                                                                          F mol                                                                              day                                                                              day                                                                              day                                                                              day                             Ex. No.                                                                            cement                                                                            SiO.sub.2                                                                        CaO                                                                              Al.sub.2 O.sub.3                                                                  Fe.sub.2 O.sub.3                                                                  MgO                                                                              K.sub.2 O                                                                        P.sub.2 O.sub.5                                                                  Cl                                                                              C/S                                                                              3  7  28 91 Ca(OH).sub.2 .sup.b)         __________________________________________________________________________    Ex. 5-1                                                                            2.0 33.4                                                                             33.9                                                                             14.2                                                                              5.0 2.4                                                                              1.43                                                                             7.0                                                                              0.0                                                                             1.10                                                                             278                                                                              441                                                                              638                                                                              687                                                                              ⊚             Ex. 5-1                                                                            3.0 "  "  "   "   "  "  "  " "  367                                                                              513                                                                              677                                                                              738                             Ex. 5-2                                                                            2.0 "  "  "   "   "  "  "  " "  254                                                                              400                                                                              599                                                                              760                                                                              ◯                Ex. 5-2                                                                            3.0 "  "  "   "   "  "  "  " "  304                                                                              443                                                                              636                                                                              810                             Ex. 5-3                                                                            2.0 "  "  "   "   "  "  "  " "  182                                                                              284                                                                              533                                                                              670                                                                              Δ                      Ex. 5-3                                                                            3.0 "  "  "   "   "  "  "  " "  211                                                                              369                                                                              528                                                                              685                             Ex. 5-4                                                                            2.0 46.3                                                                              9.4                                                                             18.4                                                                              9.0 3.0                                                                              4.09                                                                             14.1                                                                             0.0                                                                             0.21                                                                             301                                                                              452                                                                              635                                                                              739                                                                              ◯                Ex. 5-4                                                                            3.0 "  "  "   "   "  "  "  " "  371                                                                              492                                                                              636                                                                              751                             Ex. 5-5                                                                            2.0 "  "  "   "   "  "  "  " "  246                                                                              371                                                                              574                                                                              718                                                                              Δ                      Ex. 5-5                                                                            3.0 "  "  "   "   "  "  "  " "  277                                                                              379                                                                              555                                                                              688                             Ex. 5-6                                                                            2.0 "  "  "   "   "  "  "  " "  159                                                                              229                                                                              335                                                                              373                                                                              X                            Ex. 5-6                                                                            3.0 "  "  "   "   "  "  "  " "  161                                                                              243                                                                              323                                                                              352                             Ex. 5-7                                                                            2.0 38.1                                                                             19.6                                                                             17.2                                                                              12.1                                                                              3.2                                                                              3.95                                                                             1.6                                                                              0.2                                                                             0.53                                                                             272                                                                              467                                                                              598                                                                              728                                                                              ◯                Ex. 5-7                                                                            3.0 "  "  "   "   "  "  "  " "  359                                                                              467                                                                              608                                                                              714                             Ex. 5-8                                                                            2.0 "  "  "   "   "  "  "  " "  237                                                                              412                                                                              559                                                                              726                                                                              Δ                      Ex. 5-8                                                                            3.0 "  "  "   "   "  "  "  " "  259                                                                              387                                                                              547                                                                              656                             Ex. 5-9                                                                            2.0 "  "  "   "   "  "  "  " "  159                                                                              261                                                                              423                                                                              569                                                                              X                            Ex. 5-9                                                                            3.0 "  "  "   "   "  "  "  " "  152                                                                              230                                                                              385                                                                              453                             Ex. 5-10                                                                           2.0 36.6                                                                             21.5                                                                             18.8                                                                              8.2 3.7                                                                              4.57                                                                             2.6                                                                              0.3                                                                             0.63                                                                             281                                                                              454                                                                              626                                                                              724                                                                              ◯                Ex. 5-10                                                                           3.0 "  "  "   "   "  "  "  " "  374                                                                              463                                                                              644                                                                              734                             Ex. 5-11                                                                           2.0 "  "  "   "   "  "  "  " "  221                                                                              363                                                                              561                                                                              613                                                                              Δ                      Ex. 5-11                                                                           3.0 "  "  "   "   "  "  "  " "  266                                                                              371                                                                              542                                                                              686                             Ex. 5-12                                                                           2.0 "  "  "   "   "  "  "  " "  135                                                                              224                                                                              376                                                                              455                                                                              X                            Ex. 5-12                                                                           3.0 "  "  "   "   "  "  "  " "  144                                                                              217                                                                              349                                                                              427                             Ex. 5-25                                                                           3.0                             342                                                                              486                                                                              652                                                                              721                             C. Ex. 5-1                                                                         2.0 32.2                                                                             41.3                                                                             15.0                                                                              1.0 7.8                                                                              -- -- --                                                                              1.37                                                                             278                                                                              460                                                                              614                                                                              668                                                                              ⊚             C. Ex. 5-2                                                                         "   "  "  "   "   "  "  "  " "  265                                                                              454                                                                              619                                                                              728                                                                              ◯                C. Ex. 5-3                                                                         "   "  "  "   "   "  "  "  " "  213                                                                              369                                                                              586                                                                              705                                                                              □                 C. Ex. 5-4                                                                         "   (Ordinary portland cement)  282                                                                              454                                                                              626                                                                              716                                                                              ⊚             __________________________________________________________________________     (Note) C. Ex.: Comparative Example                                            1) Pulverized degree of slag (Blaine value): 4500 cm.sup.2 /g                 .sup.a) Compressive strength of mortar after being cured in water             .sup.b) Amounts of remaining Ca(OH).sub.2                                     ⊚ Considerably great amount                                    ◯ Great amount                                                    □ Small amount                                                     Δ Very small amount                                                     X None                                                                   

                                      TABLE 15                                    __________________________________________________________________________                                         Steam curing                             Slag composition (wt. %)         Mixing                                                                            time & compres-                                                        Ratio                                                                            ratio                                                                             sive strength                                                          by with                                                                              (kgf/cm)                                                               mol                                                                              portland                                                                          (Steam curing)                           Ex. No.                                                                            SiO.sub.2                                                                        CaO                                                                              Al.sub.2 O.sub.3                                                                  Fe.sub.2 O.sub.3                                                                  MgO                                                                              Na.sub.2 O                                                                       P.sub.2 O.sub.5                                                                  F C/S                                                                              cement                                                                            12 hours                                 __________________________________________________________________________                                     P:Slag                                       Ex. 5-13                                                                           50 0  30  5   5  5  5  0 0  80:20                                                                             333.3                                    Ex. 5-14                                                                           "  "  "   "   "  "  "  0 "  60:20                                                                             277.7                                    Ex. 5-15                                                                           60 0  20  5   5  5  2.5                                                                              2.5                                                                             "  80:20                                                                             301.8                                    Ex. 5-16                                                                           "  "  "   "   "  "  "  " "  60:40                                                                             310.1                                    Ex. 5-17                                                                           65 0  15  5   5  5  0  5 "  80:20                                                                             312.4                                    Ex. 5-18                                                                           "  "  "   "   "  "  0  " "  60:20                                                                             324.5                                    Ex. 5-19                                                                           85 0  0   10  0  5  0  0 "  80:20                                                                             328.6 (slag                                                                   Blaine: 4500)                            Ex. 5-20                                                                           85 0  0   10  0  5  0  0 "  60:40                                                                             292.4 (slag                                                                   Blaine: 4500)                            Ex. 5-21                                                                           90 0  0   0   0  5  0  5 "  80:20                                                                             409.8 (slag                                                                   Blaine: 4500)                            Ex. 5-22                                                                           90 0  0   0   0  5  0  5 "  60:40                                                                             362.6 (slag                                                                   Blaine: 4500)                            Ex. 5-23                                                                           50 0  0   10  15 15 10 0 0  80:20                                                                             297.1 (slag                                                                   Blaine: 4500)                            Ex. 5-24                                                                           "  "  "   "   "  "  "  " "  60:40                                                                             188.1 (slag                                                                   Blaine: 4500)                            C. Ex. 5-5                                                                         (Ordinary portland cement)      342                                      C. Ex. 5-6                                                                         Mixture of portland cement  P:Sand                                            and crushed product of ISO  80:20                                                                             281                                           standard sand                                                            C. Ex. 5-7                                                                         Mixture of portland cement  60:40                                                                             158                                           and crushed product of ISO                                                    standard sand                                                                 (Blaine value: 4500 cm.sup.2 /g)                                         __________________________________________________________________________     (Note)                                                                        P: portland cement                                                            1) Amounts of remaining Ca(OH).sub.2                                          ⊚ Considerably great amount                                    ◯ Great amount                                                    □ Small amount                                                     Δ Very small amount                                                     X None                                                                        2) Pulverized degree of mixed slag (Blaine value):                            3000 cm.sup.2 /g, partly 4500 cm.sup.2 /g included                       

Industrial Utility

The hardening composition of the present invention provides hardenedproducts having excellent strength when it is simply mixed with waterand cured. Therefore, it can be advantageously incorporated into varioustypes of concrete materials and also can be used as a variety ofsettable fillers. Moreover, through use of the composition,refuse-incinerated ashes and sewage sludge can be effectively utilizedand recycled as a resource.

We claim:
 1. A hardening composition comprising (A') a slag compositionselected from the group consisting of sewerage sludge-incinerated fusedslag, fused slag produced from municipal refuse-incinerated substances,crushed stone sludge-incinerated fused slag, concrete waste-incineratedfused slag, and fly ash-incinerated fused slag; and(B') an alkalineactivator,and wherein said slag composition contains CaO and SiO₂ in aweight ratio of CaO to SiO₂ of ≦1, and wherein said slag contains alkalicomponent(s) in an amount of 1-10 weight percent.
 2. The hardeningcomposition according to claim 1, wherein the slag composition (A') isin the form of powders, granules, or grains.
 3. The hardeningcomposition according to claim 1, wherein the alkaline activator isselected from the group consisting of alkali metal hydroxides, alkalineearth metal hydroxide, alkali metal salts of weak acids, and alkalineearth metal salts of weak acids.
 4. The hardening composition accordingto claim 1, wherein the alkaline activator (B') is a portland cementcomposition.
 5. A hardened product obtained through curing of a mixtureof the hardening composition as defined in claim 1 and water.
 6. Ahardened product obtained through curing of a mixture of the hardeningcomposition as defined in claim 1, water, and an aggregate selected fromsand, gravel, crushed stone, lightweight aggregate, or the slagcomposition (A') in coarsely crushed form.
 7. The hardened productaccording to claim 6, wherein the aggregate is the slag composition (A')in coarsely crushed form.
 8. The hardening composition according toclaim 1, wherein the slag composition contains halogen in an amount of0.1 to 10 weight percent.
 9. The hardening composition according toclaim 8, wherein the slag composition contains halogen in an amount of0.1 to 8 weight percent.